•r-w LIBRARY OF 1885- IQ56 INSECT ARCHITECTURE: TO WHICH ARE ADDED, MISCELLANIES, ON THE RAVAGES, THE PRESERVATION FOR PURPOSES OF STUDY, AND THE CLASSIFICATION, OF INSECTS. JAMES RENNIE, A.M. A NEW EDITION, REVISED. IN TWO VOLUMES.— V0LU3IE I. LONDON: CHARLES KNIGHT & Co., LUDGATE STREET. 1845. London : Printed bv William Clowes and Sons, Stamford Street. ( iii ) CONTENTS OF VOL. I. CHAPTER I. Introduction. Instruction derivable from common things . Extraordinary numbers and varieties of Insects Can be studied in every situation « Anecdotes ..... Cabinets useful, but not indispensable Study of insects does not narrow the mind Injuries and benefits caused by insects Use of names in Natural Historj' Study of Insects fascinating to youth Anecdote of a little girl . Beauty of Insects . . Varieties in the economy of Insects States of Insects .... Insects produced from eggs . Larva, Caterpillar, Grub, Maggot Pupa, Ciirysalis, Amelia, Nymjjh Imago, jjerfect Insect . CHAPTER II. Structures for protecting Eggs . . . . . Eggs of Insects can bear great degrees of lieat and cvild ..... Bees compared to our mechanics Miisoji-Wasps .... Curious proceedings of one at Lee Her caution outwitted by a Fly. Structures of another Mason-Wasp Her storing of live Caterpillars . Mason-Bees ..... Nest of one on the wall of Greenwich Par] Clay-mine of Mason -Bees at Lee Estimate of their labours . Wall- Mason Bees of France Proceedings of the two-horned Mason-Bee at Lee Structures of Mason-Bees . • • • Their restless disposition .... a2 IV CONTENTS. PAGE Mining-Bees , . . . . . . .46 Their different proceedings in Britain and in France 47 CHAPTER III. Cavpenter-Bees • . . • Methods of working . • History of one at Lee . . Violet Carpenter-Bee of France . Compared with our joiners . Elder and Bramble Carpenter-Bees Carpenter- Wasps .... Curious cocoon of . . . Upholsterer-Bees .... Poppy-flower Bee of Largs and of Bercy Taste of the little architects in ornament Cotton-gathering Bee . . . Rose-Leaf-cutfer Bee . • Her method of working . . Anecdote of St. Francis Xavier . CHAPTER IV. Carder-BeeS) ,.*.".... IMethod of preparing and conveying their material Structure of their nests Lapidary-Bees .... Pertinacity in defending their nest Humble-Bees .... Structure of their nests Social-Wasps .... Nest founded by a single female Compared with the Burrowing-Owl Materials rasped off irom wood . Different opinions of Naturalists Paper made by Wasps Structure of the nest . . Extraordinary number of cells . Hornet's nest .... Ti'ee- Wasps' nests in Ayrshire , Rose-shaped Wasps'-nest . . Vertical Wasps'-nest W'asp-paper compared with ours Canl-making Wasp of Cayenne CO>'TENTS. CHAPTER V. Architecture of the Hive- Bee . . . . . Discoveries from Aristonxachus to iNFaruldi and Huber ..... Nurse-Bees and Wax-workers . Preparation of wax . . Erroneous account by the Abbe la Pluche Conjectures of Reaumur . , Discovery of John Hunter Experiments of M. Huber Singular facts by Mr. Wiston . Dissections by Madlle. Jurine and M. Latreille Propolis ...... Opinions of Old Naturalists Discovery by Huber Various uses of propolis . Mr. T. A. Knight's observations. Basket for carrying on the thiglis of Bees Process of loading . . . Building of the cells . * Division of labour . Festooned curtain of Wax-workers Commencement of the combs Hiiber's history of liis experiments Secretion of wax Foundation of the first cell Workers extract their own wax . View of the proceedings obstructed CHAPTER VI. Form of the cells ..... Mathematical problem solved by Bees Calculated by Maraldi and Koenig . Reasons for the form of the cells . . Referred to the form of the Bee . Experiments of Huber Cells commenced in the foundation-wall Deepening of the cells . . . Polishing by Nurse-Bees . Distance of the coml)s from each otlier Dr. Barclay's discovery • . Inegularities in their workmanship . . Anecdote from Dr. Bevan PAGE 90 Vi CONTENTS. Similar anecdote from Huber Symmetry in the architecture of Bees explained Curved comhs Experiments of Huber Size of male cells . Cells enlarged v/ben honey is plentiful The linishing of the cells "\'arnisbed with pro})olis . Strengthened with pissoceros Discovery by Huber Cells strengthened by the Bee-grubs Difficulties explained Mistake of an American v/rlter Curious exjoeriment of Huber Wild-Honey Bees . Wild-Bees of America, Ireland, Palestine Honey-guide of Africa Bee-hunting iu America CHAPTER VII. Car})entry of Tree-hoppers ( Cicadai) Mistaken for Grass-hojipers Singular cutting Instrument of the Tree-hopper Double files of . Their nests . • Sav/-Flles Their ovipositor Structure of . Comb-toothed rasp, and saw Grooves cut by It in the rose-tree CHAPTEPv Vni. Leaf-rolling Caterpillars . Lilac-Leaf Roller * , . Oak-Leaf Roller . Rose- Leaf Roller Nettle-Leaf Roller . Method of proceeding . . Probable mistake concerning Sorrel-Leaf Roller . , Admirable and Painted La/-ly Butterfl Mallow-Butterfly of France ' . Willow-Leaf Bundler . COUTEMTS. VU Nest of Zlczac Caterpillar ' . . Nest of Glanville Fritillary Experiment on gregarious Caterpillars by J. U. Design in rolling leaves . • • . VAGE 164 1(J4 loa 167 CHAPTER IX. Habitations formed of detached leaves The Pondweed Tent-maker Chickweed Caterpillar's nest Cypress-spurge Caterpillar's nest Durability of these structures . Moss-cell of a Wall-Calerpillar Caterpillar of Greenwich P;uk wall 16S 169 170 171 171 173 173 CHAPTER X. Caddis-Worms . . Leaf and reed nests of Shell nests of. Stone and sand nests of Nest balanced with straws Carpenter-Caterpillars Caterpillar of Goat-Moth . Its winter nest . Singular nest of . - . Nest of the vEgeria in a Poplar . Paper-nest of the Puss-Zslotli How it escapes from its cell Purple-Capricorn Beetle Bark-building Caterpillar of the oak 175 175 176 177 178 179 179 ISO 181 181 183 184 185 186 CHAPTER XI. Eartli-mason Cater})illar3 Outside walls oftbeirnest Caterpillar of Ghost-Moth Experiments of Reaumur . . Nests of Ephemera Grubs . Similar nests in a willow stinnp Nests of the Cincindela- Beetle . The Ant-Lion ... Structure of the Grub . . 189 190 leo 192 195 195 196 197 198 vm CONTENTS. Formation of its traps jRefleclioiis u|;on tlie economy ol" Nature 199 203 . CHAPTER XII. 'Clothes-Mo tlj Caterpillars Varieties in the species IMethods of destroying Mode of building . Experiments upon » Migrations of. . Tent-Making Caterpillars Mode of constructing these Experiments upon . Tent upon a Nettle-leaf Stone-Mason Caterpillars Their singular proceedings Colony of, at Blackheath Foundation of their tents An attempted robbery Muft-shaped Tents . Their utility . Leaf. Mining Caterpillars On the leaf of the Monthly Rose-tree On the leaf of the Bramble On the leaf of the Primrose Vine-leaf Miner On the leaf of the Alder . Social Leaf-Miners . Bark-mining Caterpillars CHAPTER XIII. Structures of Crickets The House-Cricket The Mole-Cricket . The Field-Cricket . Mode of depositing eggs Beetles The Burying-Beetle The Dung-Beetle . Its cleanliness The Rose-Cliafer . The Tumble-dung Beetle The Necklace-Beetle ( 9 ) INSECT ARCHITECTURE. CHAPTER I. INTRODUCTION. It can never be too strongly impressed upon a mind anxious for the acquisition of knowledge, that the com- monest things by which we are surrounded are deserving of minute and careful attention. The most profound investigations of Philosophy are necessarily connected with the ordinary circumstances of our being, and of the world in which our every-day life is spent. With re- gard to our ov.n existence, the pulsation of the heart, the act of respiration, the voluntary movement of our limbs, the condition of sleep, are among the most ordi- nary operations of our nature ; and yet how long were the wisest of men struggling with dark and bewildering speculations before they could ofter anything like a satis- factory solution of these phenomena, and how far are we still from an accurate and complete knowledge of them ! The science of Meteorology, which attempts to explain to us the philosophy of matters constantly be- fore our eyes, as dew, mist, and rain, is dependent for its illustrations upon a knowledge of the most compli- cated facts, such as the influence of l.eat and electricity upon the air ; and this knowledge is at present so im- perfect, that even these common occun'ences of the weather, which men have been observing and reasoning upon for ages, are by no means satisfactorily explained, or reduced to the precision that every science should aspire VOL. I. B 10 INSECT AKCHITECTUBE. to. Yet, however difficult it may be entirely to com- prehend the phenomena we daily witness, every thing in nature is full of instruction. Thus the humblest flower of the field, although, to one whose curiosity has not been excited, and whose understanding has, there- fore, remained uninformed, it may appear worthless and contemptible, is valuable to the botanist, not only with regard to its place in the arrangement of this portion of the Creator's works, but as it leads his mind forward to the consideration of those beautiful provisions for the support of vegetable life, which it is the part of the phy- siologist to study and to admire. This train of reasoning is peculiarly applicable to the economy of insects. They constitute a very large and interesting part of the animal kingdom. They are everywhere about us. The spider weaves his curious web in our houses ; the caterpillar constructs his silken cell in our gardens ; the wasp that hovers over our food has a nest not far removed from us, which she has assisted to build with the nicest art ; the beetle that crawls across our path is also an ingenious and laborious mechanic, and has some curious instincts to exhibit to those who will feel an interest in watching his movements ; and the moth that eats into our clothes has something to plead for our pity, for he came, like us, naked into the world, and he has destroyed our garments, not in malice or wantonness, but that he may clothe himself with the same wool which we have stripped from the sheep. An observation of the habits of these little creatures is full of valuable lessons, which the abundance of the examples has no tendency to diminish. The more such observa- tions are multiplied, the more are we led forward to the freshest and the most delightful parts of knowledge ; the more do we learn to estimate rightly the extraordinary provisions and most abundant resources of a creative Providence ; and the better do we appreciate our own relations with all the infinite varieties of Nature, and ojT dependence, in common with the ephemeron that flutters its little hour in the summer sun, upon that Being in whose scheme of existence the humblest as well as the INTKODUCTIOX. 11. highest creature has its destined purposes. " If you speak of a stone," says St. Basil, one of the Fathers of the Church, *' if you speak of a fly, a gnat, or a bee, your conversation will be a sort of demonstration of His power whose hand formed them, for the wisdom of the workman is commonly perceived in that which is of little size. He who has stretched out the heavens, and dug up the bottom of the sea, is also He who has pierced a passage through the sting of the bee for the ejection of its poison." If it be granted that making discoveries is one of the most satisfactory of human pleasures, then we may with- out hesitation affirm, that the study of insects is one of the most delightful branches of natural history, for it affords peculiar facilities for its pursuit. These facilities are found in the almost inexhaustible variety which in- sects present to the curious observer. As a proof of the extraordinary number of insects within a limited field of observation, Mr. Stephens informs us, that in the short space of forty days, between the middle of June and the beginning of August, he found, in the vicinity of Ripley, specimens of above two thousand four hundred species of insects exclusive of caterpillars and grubs, — a number amounting to nearly a fourth of the insects ascertained to be indigenous. He further tells us, that, among these specimens, although the ground had, in former seasons, been frequently explored, there were about one hundred species altogether new, and not before in any collection which he had inspected, including several new genera ; while many insects reputed scarce were in considerable plenty.* The localities of insects are, to a certain ex- tent, constantly changing ; and thus the study of them has, in this circumstance, as well as in their manifold abundance, a source of perpetual variety. Insects, also, which are plentiful one year, frequently become scarce, or disappear altogether, the next — a fact strikingly illus- trated by the uncommon abundance, in 1826 and 1827, of the seven-spot lady-bird {Coccinella septempunc- * Stephens's Illustrations, vol. i., p. 72, note. B 2 12 INSECT ABCHITECTUBE. tatd), in the vicinity of London, though during the two succeeding summers this insect was comparatively scarce, while the small two-spot lady-bird (^Coccinella bipunc- tatd) was plentiful. There is, perhaps, no situation in which the lover of nature and the observer of animal life may not find op- portunities for increasing his store of facts. It is told of a state prisoner under a cruel and rigorous despotism, that when he was excluded from all commerce with mankind, and was shut out from books, he took an in- terest and found consolation in the visits of a spider ; and there is no improbability in the story. The opera- tions of that persecuted creature are among the most extraordinary exhibitions of mechanical ingenuity ; and a daily watching of the workings of its instinct would beget admiration in a rightly constituted mind. The poor prisoner had abundant leisure for the speculations in which the spider's web would enchain his understand- ing. We have all of us, at one period or other of our lives, been struck with some singular evidence of con- trivance in the economy of insects, which we have seen w^ith our own eyes. Want of leisure, and probably want of knowledge, have prevented us from following up the curiosity which for a] moment was excited. And yet some such accident has made men Naturalists, in the highest meaning of the term. Bonnet, evidently speak- ing of himself, says, " I knew^ a naturalist, who, when he was seventeen years of age, having heard of the operations of the ant-lion, began by doubting them. He had no rest till he had examined into them ; and he verified them, he admired them, he discovered new facts, and soon became the disciple and the friend of the Pliny of France " * (Reaumur). It is not the happy fortune of many to be able to devote themselves exclu- sively to the study of nature, unquestionably the most fascinating of human employments ; but almost every one may acquire sufficient knowledge to be able to derive a high gratification from beholding the more common * Contemplation de la Nature, part ii. ch. 42. INTRODUCTION. 1 3 operations of animal life. His materials for contem- plation are always before him. Some weeks ago we made an excursion to West Wood, near Shooter's Hill, expressly for the purpose of observing the insects we might meet with in the wood : but we had not got far among the bushes, when heavy rain came on. We im- mediately sought shelter among the boughs of some thick" underwood, composed of oak, birch, and aspen; but we could not meet with a single insect, not even a gnat or a fly, sheltered under the leaves. Upon look- ing more narrowly, however, into the bushes which protected us, we soon found a variety of interesting objects of study. The oak abounded in galls, several of them quite new to us ; while the leaves of the birch and the aspen exhibited the curious serpentine paths of the minute mining caterpillars. When we had exhausted the narrow field of observation immediately around us, we found that we could considerably extend it, by breaking a few of the taller branches near us, and then examining their leaves at leisure. In this manner two hours glided quickly and pleasantly away, by which time the rain had nearly ceased, and though we had been disappointed in our wish to ramble through the wood, we did not return without adding a few interest- ing facts to our previous knowledge of insect economy.* It will appear, then, from the preceding observations, that cabinets and collections, though undoubtedly of the highest use, are by no means indispensable, as the ob- server of nature may find inexhaustible subjects of study in every garden and in every hedge. Nature has been profuse enough in affording us materials for observation, when we are prepared to look about us with that keen- ness of inquiry, which curiosity, the first step in the pursuit of knowledge, will unquestionably give. Nor shall we be disappointed in the gratification which is thus within our reach. Were it no more, indeed, than a source of agreeable amusement, the study of insects * The original observations in this volume which are marked by the initials J. R., are by J. Rennie, A.M., A.L.S. 14 INSECT ARCHITECTURE. comes strongly recommended to the notice of the well- educated. The pleasures of childhood are generally supposed to be more exquisite, and to contain less alloy, than those of riper years ; and if so, it must be because then everything appears new and dressed in fresh beau- ties : while in manhood, and old age, whatever has fre- quently recurred begins to -wear the tarnish of decay. The study of nature affords us a succession of " ever new delights," such as charmed us in childhood, when everything had the attractions of novelty and beautj' ; and thus the mind of the naturalist may have its own fresh and vigorous thoughts, even while the infirmities of age weigh down the body. It has been objected to the study of insects, as well as to that of Natural History in general, that it tends to withdraw the mind from subjects of higher moment ; that it cramps and narrows the range of thought ; and that it destroys, or at least weakens, the finer creations of the fancy. Now, we should allow this objection in its fullest extent, and even be disposed to carry it fur- ther than is usually done, if the collecting of specimens only, or, as the French expressly call them, chips (echantillons) , be called a study. But the mere collector is not, and cannot be, justly considered as a naturalist ; and, taking the term naturalist in its enlarged sense, we can adduce some distinguished instances in opposition to the objection. Rousseau, for example, was passionately fond of the Linnaean botany, even to the driest minutiae of its technicalities ; and yet it does not appear to have cramped his mind, or impoverished his imagination. If Rousseau, however, be objected to as an eccentric being, from whose pursuits no fair inference can be drawn, we give the illustrious example of Charles James Fox, and may add the names of our distinguished poets. Gold- smith, Thomson, Gray, and Darwin, who were all enthusiastic naturalists. We wish particularly to insist upon the example of Gray, because he was very partial to the study of insects. It may be new to many of our readers, who are familiar with the Elegy in a Country Church-vard, to be told that its author was at the pains INTRODUCTION. 15 to turn the characteristics of the Linnaean orders of in- sects into Latin hexameters, the manuscript of which is still preserved in his interleaved copy of the ' Systema Naturae.' Further, to use the somewhat exaggerated words of Kirby and Spence, whose work on Entomology is one of the most instructive and pleasing books on the science, *' Aristotle among the Greeks, and Pliny the Elder among the Romans, may be denominated the fathers of Natural History, as well as the greatest philosophers of their day ; yet both these made insects a principal object of their attention : and in more re- cent times, if we look abroad, what names greater than those of Redi, Malpighi, Vallisnieri, Swammerdam, Leeuwenhoek, Reaumur, Linnaeus, De Geer, Bonnet, and the Hubers ? and at home, what philosophers have done more honour to their country and to human nature than Ray, Willughby, Lister, and Derham ? Yet all these made the study of insects one of their most favourite pursuits." * And yet this study has been considered, by those who have superRcially examined the subject, as belonging to a small order of minds ; and the satire of Pope has been indiscriminately applied to all collectors, while, in truth, it only touches those who mistake the means of know- ledge for the end : — " O ! would the sons of men once think their eyes And reason given them but to study Flies ! See Nature, in some partial, narrow shape, And let the Author of the whole escape ; Learn but to trifle ; or, who most observe, To wonder at their Maker, not to serve." f Thus exclaims the Goddess of Dulness, sweeping into her net all those who study nature in detail. But if the matter were rightly appreciated, it would be evident that no part of the works of the Creator can be without the deepest interest to an inquiring mind ; and that a portion * Introduction to Entomology, vol. i. f Dunciad, book iv. 16 INSECT ARCHITKCTLRE. of creation which exhibits such extraordinary manifesta- tions of design as is shown by insects must have attrac- tions for the very highest understanding. An accurate knowledge of the properties of insects is of great importance to man, merely with relation to his own comfort and security. The injuries which they inflict upon us are extensive and complicated ; and the remedies which we attempt, by the destruction of those creatures, both insects, birds and quadrupeds, who keep the ravages in check, are generally aggravations of the evil, because they are directed by an ignorance of the economy of nature. The little knowledge which we have of the modes by which insects may be impeded in their destruction of much that is valuable to us, has pro- bably proceeded from our contempt of their individual insignificance. The security of property has ceased to be endangered by quadrupeds of prey, and yet our gardens are ravaged by aphides and caterpillars. It is somewhat startling to ainrm that the condition of the human race is seriously injured by these petty annoy- ances ; but it is perfectly true that the art and industry of man have not yet been able to overcome the collective force, the individual perseverance, and the complicated machinery of destruction which insects employ. A small ant, according to a most careful and philosophical ob- server, opposes almost invincible obstacles to the progress of civilization in many parts of the equinoctial zone. These animals devour paper and parchment ; they destroy every book and manuscript, xvlany provinces of Spanish America cannot, in consequence, show a written docu- ment of a hundred years' existence. " What develop- ment," he adds, " can the civilization of a people assume, if there be nothing to connect the present with the past — if thejdepositories of human knowledge must be con- stantly renewed — if the monuments of genius and w is- dom cannot be transmitted to posterity ? " * Again, there are beetles which deposits their larvag in trees in such formidable numbers that whole forests perish be- * Humboldt, Voyage, lib. vii., cb. 20. INTEODUCTIOJf. 17 vond the power of remedy. The pines of the Hartz have thus been destroyed to an enormous extent ; and in North America, at one place in South Carolina, at least ninety trees in every hundred, upon a tract of two thou- sand acres, were swept away by a small black, winged bug. And yet, according to Wilson, the historian of American birds, the people of the United States were in tlie habit of destroying the red-headed woodpecker, the great enemy of these insects, because he occasionally spoilt an apple.* The same delightful writer and true naturalist, speaking of the labours of the ivory-billed woodpecker, says, " Would it be believed that the larvae of an insect or fly, no larger than a grain of rice, should silently, and in one season, destroy some thousand acres of pine-ti'ees, many of them from two to three feet in diameter, and a hundred and fifty feet high ? In some places the whole woods, as far as you can see around you, are dead, stripi^ed of the bark, their wintry-looking arms and bare trunks bleaching in the sun, and tumbling in ruins before every blast." f The subterraneous larva of some species of beetle has often caused a complete failure of the seed-corn, as in the district of Halle in 18 12. J The corn-weevil, which extracts the flour from grain, leaving the husk behind, will destroy the contents of the largest storehouses in a very short period. The wire-worm and the turnip-fly are dreaded by every farmer. The ravages of the locust are too well known not to be at once recollected as an example of the for- midable collective power of the insect race. The white ants of tropical countries sweep away whole villages with as much certainty as a fire or an inundation ; and ships even have been destroyed by these indefatigable repub- lics. Our own docks and embankments have been threatened by such minute ravagers. The enormous injuries which insects cause to man may thus be held as one reason for ceasing to consider the study of them as an insignificant pursuit ; for a know- * Amer. Ornith., 5., p. 144. f lb. in., p. 21. + Blumenbach ; see also Insect Transformations, p. 231. B 3 18 INSECT AECHITECTURE. ledge of their structure, their food, their enemies, and their general habits, may lead, as it often has led, to the means of guarding against their injuries. At the same time we derive from them both direct and indirect bene- fits. The honey of the bee, the dye of the cochineal, and the web of the silk-worm, the advantages of which are obvious, may well be balanced against the destructive propensities of insects which are offensive to man. But a philosophical study of natural history will teach us that the direct benefits which insects confer upon us are even less important than their general uses in maintaining the economy of the world. The mischiefs which result to us from the rapid increase and the activity of insects are merely results of the very principle by which they confer upon us numberless indirect advantages. Forests are swept away by minute beetles ; but the same agencies relieve us from that extreme abundance of vegetable matter which would render the earth uninhabitable were this excess not periodically destroyed. In hot countries, the great business of removing corrupt animal matter, which the vulture and the hyaena imperfectly perform, is effected with certainty and speed by the myriads of in- sects that spring from the eggs deposited in every carcase by some fly seeking therein the means of life for her pro- geny. Destruction and reproduction, the great laws of Nature, are carried on very greatly through the instru- mentality of insects ; and the same principle regulates even the increase of particular species of insects them- selves. When aphides are so abundant that we know not how to escape their ravages, flocks of lady-birds in- stantly cover our fields and gardens to destroy them. Such considerations as these are thrown out to show that the subject of insects has a great philosophical import- ance — and what portion of the works of Nature has not ? The habits of all God's creatures, whether they are noxi- ous, or harmless, or beneficial, are worthy objects of our study. If they affect ourselves, in our health or our posses- sions, whether for good or for evil, an additional impulse is naturally given to our desire to attain a knowledge of their properties. Such studies form one of the most INTRODUCTION. 1 9 interesting occupations which can engage a rational and inquisitive mind ; and, perhaps, none of the employments of human life are more dignified than the investigation and survey of the workings and the ways of Nature in the minutest of her productions/ The exercise of that habit of observation which can alone make a naturalist — " an out-of-door naturalist," as Daines Barrington called himself — is well calculated to strengthen even the most practical and merely useful powers of the mind. One of the most valuable mental acquirements is the povi'er of discriminating among things which differ in many minute points, but whose general similarity of appearance usually deceives the common observer into a belief of their identity. The study ot insects, in this point of view, is most peculiarly adapted for youth. According to' our experience, it is exceed- ingly difficult for persons arrived at manhood to acquire this power of discrimination ; but, in early life, a little care on the part of the parent or teacher will render it comparatively easy. In this study the knowledge of things should go along with that of words. " If names perish," says Linnaeus, "the knowledge of things pe- rishes also :" * and, without names, how can any one com- municate to another the knowledge he has acquired rela- tive to any particular fact, either of physiology, habit, utility, or locality ? On the other hand, mere catalogue learning is as much to be rejected as the loose gene- ralizations of the despisers of classification and nomencla- ture. To name a plant, or an insect, or a bird, or a quadruped rightly, is one step towards an accurate know- ledge of it ; but it is not the knowledge itself. It is the means, and not the end, in natural history, as in every other science. If the bias of opening curiosity be properly directed, there is not any branch of natural history so fascinating to youth as the study of insects. It is, indeed, a common practice in many families to teach children, from their earliest infancy, to treat the greater number of insects as * Nomina si pereauf, perit et cognitio lerum. 20 INSECT ARCHITECTURE. if they were venomous and dangerous, and, of course, meriting to be destroyed, or at least avoided with horror. Associations are by this means linked with the very ap- pearance of insects, which become gradually more invete- rate with advancing years ; provided, as most frequently happens, the same system be persisted in, of avoiding or destroying almost every insect which is unlucky enough to attract observation. How much rational amusement and innocent pleasure is thus thoughtlessly lost ; and how many disagreeable feelings are thus created, in the most absurd manner ! '* In order to show that the study or (if the word be disliked) the observation of insects is peculiarly fascinating to children, even in their early infancy, we may refer to what we have seen in the family of a friend, who is partial to this, as well as to all the departments of natural history. Our friend's children, a boy and girl, were taught, from the moment they could distinguish insects, to treat them as objects of interest and curiosity, and not to be afraid even of those which wore the most repulsive appearance. The little girl, for ex- ample, when just beginning to walk alone, encountered one day a large staphylinus ( Goerius olens ? Stephens ; vulgo, the devil's coach-horse), which she fearlessly seized, and did not quit her hold, though the insect grasped one of her fingers in his formidable jaws. The mother, who was by, knew enough of the insect to be rather alarmed for the consequences, though she prudently con- cealed her feelings from the child. She did well ; for the insect was not strong enough to break the skin, and the child took no notice of its attempts to bite her finger. A whole series of disagreeable associations with this formidable-looking family of insects was thus averted at the very moment when a different mode of acting on the part of the mother would have produced the contrary effect. For more than two years after this occurrence the little girl and her brother assisted in adding nume- rous specimens to their father's collection, without the parents ever having had cause, from any accident, to repent of their employing themselves in this manner. The sequel of the little girl's history strikingly illustrates IXTRODUCTIOK. 21 the position for which we contend. The child happened to be sent to a relative in the country, where she was not long in having carefully instilled into her mind all the usual antipathies against ''everything that creepeth on the earth ;" and though she afterwards returned to her paternal home, no persuasion nor remonstrance could ever again persuade her to touch a common beetle, much less a staphylinus, with its tail turned up in a threatening attitude, and its formidable jaws ready extended for attack or defence.* We do not wish that children should be encouraged to expose themselves to danger in their encounters with insects. They should be taught to avoid those few which are really noxious — to admire all — to injure none. The various beauty of insects — their glittering colours, their graceful forms — supplies an inexhaustible source of attraction. Even the most formidable insects, both in appearance and reality, — the dragon-fly, which is per- fectly harmless to man, and the wasp, whose 'sting every human being almost instinctively shuns, — are splendid in their appearance, and are painted with all the brilliancy of natural hues. It has been remarked, that the plumage of tropical birds is not superior in vivid colouring to what may be observed in the greater number of butterflies and moths, t "See," exclaims Linnaeus, "the large, ele- gant painted wings of the butterfly, four in number, covered with delicate feathery scales ! With these it sustains itself in the air a whole day, rivalling the fligjit of birds and the brilliancy of the peacock. Consider this insect through the wonderful progress of its life, — how different is the first period of its being from the second, and both from the parent insect ! Its changes are an inexplicable enigma to us : we see a green cater- pillar, furnished with sixteen feet, feeding upon the leaves of a plant ; this is changed into a chrysalis, smooth, of golden lustre, hanging suspended to a fixed point, with- out feet, and subsisting without food ; this insect again * J. R. in Mag. of Natural History, vol. i., p. 334. f Miss Jermyn's Butterfly Collector, p. 11. 22 IXSECT APXHITECTURE. undergoes another transformation, acquires wings, and six feet, and becomes a gay butterfly, sporting in the air, and living by suction upon the honey of plants. What has Nature produced more worthy of our admiration than such an animal coming upon the stage of the world, and playing its part thereunder so many different masks?" The ancients were so struck with the transformations of the butterfly, and its revival from a seeming temporary death, as to have considered it an emblem of the soul, the Greek word psyclie signifying both the soul and a butterfly ; and it is for this reason that we find the but- terfly introduced into their allegorical sculptures as an emblem of immortality. Trifling, therefore, and per- haps contemptible, as to the unthinking may seem the study of a butterfly, yet when we consider the art and mechanism displayed in so minute a structure, — the fluids circulating in vessels so small as almost to escape the sight— the beauty of the wings and 'covering — and the manner in which each part is adapted for its peculiar functions, — we cannot but be struck with wonder and admiration, and allow, with Paley, that "the production of beauty was as much in the Creator's mind in painting a butterfly as in giving symmetry to the human form." A collection of insects is to the true natqralist what a collection of medals is to the accurate student of history. The mere collector, who looks only to the shining wings of the one, or the green rust of the other, derives little knowledge from his pursuit. But the cabinet of the naturalist becomes rich in the most interesting subjects of contemplation, when he regards it in the genuine spirit of scientific inquiry. What, for instance, can be so de- lightful as to examine the wonderful variety of structure in this portion of the creation ; and, above all, to trace the beautiful gradations by which one species runs into another. Their differences are so minute,* that an un- practised eye would proclaim their identity ; and yet, when the species are separated, and not very distantly, they become visible even to the common observer. It is in examinations such as these that the naturalist finds a delight of the highest order. While it is thus one of INTRODUCTION. 23 the legitimate objects of his study to attend to minute differences of structure, form, and colouring, he is not less interested in the investigation of habits and economy ; and in this respect the insect world is inexhaustibly rich. We find herein examples of instinct to parallel those of all the larger animals, whether they are solitary or social ; and innumerable others besides, altogether unlike those manifested in the superior departments of animated nature. These instincts have various directions, and are developed in a more or less striking manner to our senses, according to the force of the motive by which they are governed. Some of their instincts have for their object the preservation of insects from external attack ; some have reference to procuring food, and involve many re- markable stratagems ; some direct their social economy, and regulate the condition under which they live to- gether either in monarchies or republics, their coloniza- tions, and their migrations : but the most powerful in- stinct which belongs to insects has regard to the pre- servation of their species. We find, accordingly, that as the necessity for this preservation is of the utmost im- portance in the economy of nature, so for this especial object many insects, whose oflTspring, whether in the egg or the larva state, are peculiarly exposed to danger, are endued with an almost miraculous foresight, and with an ingenuity, perseverance, and unconquerable industry, for the purpose of avoiding those dangers, which are not to be paralleled even by the most singular efforts of human contrivance. The same ingenuity which is employed for protecting either eggs, or caterpillars and grubs, or pupae and chrysalides, is also exercised by many insects for their own preservation against the changes of temperature to which they are exposed, or against their natural enemies. Many species employ those contrivances during the period of their hybernation, or winter- sleep. For all these purposes some dig holes in the earth, and form them into cells ; others build nests of extraneous substances, such as bits of wood and leaves ; others roll up leaves into cases, which they close with the most curious art ; others build a house of mud, and line it with the cotton of trees, 24 INSECT ARCHITECTURE. or the petals of the most delicate flowers ; others con- struct cells, of secretions from their own bodies ; others form cocoons, in which' they undergo their transforma- tion ; and others dig subterraneous galleries, which, in complexity of arrangement, in solidity, and in complete adaptation to their purposes, vie with the cities of civilized man. The contrivances by which insects effect these objects have been accurately observed and minutely de- scribed, by patient and philosophical inquirers, who knew that such employments of the instinct with which each species is endowed by its Creator offered the most valu- able and instructive lessons, and opened to them a wide field of the most delightful study. The construction of their habitations is certainly among the most remarkable peculiarities in the economy of insects ; and it is of this subject that we propose to treat under the general name, which is sufficiently applicable to our purpose, of Insect Architecture. In the descriptions which we shall give of Insect Archi- tecture, we shall employ as few technical words as pos- sible ; and such as we cannot well avoid, we shall explain in their places : but, since our subject chiefly relates to the reproduction of insects, it may be useful to many readers to introduce here a brief description of the changes which they undergo. It was of old believed that insects were produced spontaneously by putrefying substances ; and Virgil gives the details of a process for creatmg a swarm of bees out of the carcase of a bull : but Redi, a celebrated Italian naturalist, proved by rigid experiments that they are always, in such cases, hatched from eggs previously laid. Most insects, indeed, lay eggs, though some few are vivi- parous, and some propagate both ways. The eggs of insects are very various in form, and seldom shaped like those of birds. We have here figured those of several species, as they appear under the microscope. When an insect first issues from the e^^, it is called IXTRODUCTIOX. b 25 Magnified eggs of a, Geometra nrmlllata ; b, of .an unknown water insect ; c, of the lacquey moth ; d, of a. caddis-fly (Phryganea atratd) ; f, of red underwing moth iCatomla nup'a)', f, of Funtia Brassicce ; g, of the Clifden Nonpareil moth. by naturalists larva, and, popularly, a caterpillar, a grub, or a maggot. The distinction, in popular language, seems tf) be, that caterpillars are produced from the eggs of moths or butterflies ; grubs from the eggs of beetles, bees, wasps, &c. ; and maggots (which are without feet) from blow-flies, house-flies, cheese-flies, &c., though this is not very rigidly adhered to in common parlance. Maggots are also sometimes called norms, as in the in- stance of the meal-worm ; but the common earth-worm is not a larva, nor is it by modern natui'alists ranked among insects. There are, however, certain larvae, as those of the Cicada, the crickets, the Mater boatsman (Notonecta), the cockroach, &c., which resemble the perfect insects in form, excepting that they are destitute of wings ; but in the pupa state these appear in a rudimentary condi- tion, at least in such species as have wings in the mature stage of existence. The pupae are active and eat. Insects, the larvae and pupae of which are so similar to the adults, are termed Ametaholous (a, without, 26 INSECT ARCHITECTURE. fiETafioXr], change) ; those the larvae of which undergo changes of a marked character, Metaholous (Insecta ametabola and Insecta metabola, Burmeister). Larvse are remarkably small at first, but grow rapidly. The full-grown caterpillar of the goat moth (Cossus ligjiipei'd^ is thus seventy-two thousand times heavier than when it issues from the egg ; and the maggot of the a, Ametabolous Pupa of Cicada; b, Caterpillar of tussock moth (^Laria fascelina) ; c, larva of the poplar beetle (^Clirysomelapopidi); d, larva of Sinex ; e, larva of the common gnat. blow-fly is, in twenty-four hours, one hundred and fifty- five times heavier than at its birth. Some larvae have feet, others are without ; none have wings. They can- not propagate. They feed voraciously on coarse sub- stances ; and as they increase in size, which they do very rapidly, they cast their skins three or four times. In defending themselves from injury, and in preparing for their change by the construction of secure abodes, they manifest great ingenuity and mechanical skill. The I>TR0DUCT10X. 27 figures on the preceding page exemplify various forms of insects in this stage of their existence. When larvae are full grown, they cast their skins for the last time, undergo a complete change of form, ex- cepting in the case of ametabolous larvae, cease to eat, and remain nearly motionless. The inner skin ot the larva nov/ becomes converted into a membranous or leathery covering, which wraps the insect closely up like a. Pupa of a water-teetle (^Hydrophilus) ; h, pup.i ofSjihinx Ligustii. a mummy ; in this condition it is termed Pupa, from its resemblance to an infant in swaddling bands. Nympha, or nymph, is another term given to insects in this stage ;* moreover from the pupae of m.any of the butterflies ap- pearing gilt as if with gold, the Greeks called them Chrysalides, and the Romans AurelicB, and hence na- turalists frequently call a pupa chrysalis, even when it is not gilt. We shall see, as we proceed, the curious con- trivances resorted to for protecting insects in this helpless state. After a certain time, the insect which has remained in its pupa-case, like a mass of jelly without shape, is gra- dually preparing for its final change, when it takes the form of a perfect insect. This state was called by Linnaeus Imago, because the insect, having thrown off * Generally to ametabolous pnpse. 28 INSECT ARCHITECTURE. its mask, becomes a perfect image of its species. Of some, this last portion of their existence is very short, others live through a year, and some exist for longer periods. They feed lightly, and never increase in size. The chief object of all is to perpetuate their species, after which the greater number quickly die. It is in this state that they exercise those remarkable instincts for the pre- servation of their race, which are exhibited in their pre- parations for the shelter of their eggs, and the nourish- ment of their larvoe. The following are examples of insects in the imagOj or perfect state. a \ / Insects in the Imago or perfect state. u, Nemopteryx coa, Leach.— 6, Myrmelcon furmkalynx, Fabricius. c, Heiperia comma, Fabricius. — d, Nepa cinered, Linn;eus. MASOX-BEES. 29 CHAPTER II. Structures for protecting Eggs, — Mason-Wasps ; Mason- Bees ; Mining-Bees. The provisions which are made by the different species of insects for protecting their eggs, appear in many cases to be admirably proportioned to the kind of danger and destruction to which they may be exposed. The eggs themselves, indeed, are not so liable to depredation and injury as the young brood hatched from them ; for, like the seeds of plants, they are capable of withstanding greater degrees both of heat and cold than the insects which produce them. According to the experiments of Spallanzani, the eggs of frogs that had been exposed to various degrees of artificial heat, were scarcely altered in their productive powers by a temperature of 111"* of Fahrenheit, but they became corrupted after 133°. He tried the same experiment upon tadpoles and frogs, and found they all died at 111°. Silk-worms died at a tem- perature of 108°, while their eggs did not entirely cease to be fertile till 144°. The larvae of flesh-flies perished, while the eggs of the same species continued fertile, at about the same comparative degrees of heat as in the pre- ceding instances. Intense cold has a still less effect upon eggs than extreme heat. Spallanzani exposed the eggs of silk-worms to an artificial cold 23° below zero, and yet, in the subsequent spring, they all produced caterpillars. Insects almost invariably die at the temperature of 14°, that is at 18° below the freezing point.* The care of insects for the protection of their eggs is not entirely directed to their preservation in the most favourable * See Spallanzani's Tracts, by Dalyel!, vol. i. 30 IXSECT ARCHITECTURE. temperature for being hatched, but to secure them against the numerous enemies which would attempt their destruc- tion ; and, above all, to protect the grubs, when they are first developed, from those injuries to which they are peculiarly exposed. Their prospective contrivances for accomplishing these objects arc in the highest degree curious. Most persons have more or less acquaintance with the hives of the social species of bees and wasps ; but little is generally known of the nests constructed by the solitary species, though in many respects these are not inferior to the others in displays of ingenuity and skill. We admire the social bees, labouring together for one com- mon end, in the same way that we look with delight upon the great division of labour in a well-ordered manufac- tory. As in a cotton -mill some attend to the carding of the raw material, some to its formation into single threads, some to the gathering these threads upon spin- dles, others to the union of many threads into one, — all labouring with invariable precision because they attend to a single object ;— so do we view with delight and wonder the successive steps by which the hive-bees bring their beautiful work to its completion, — striving, by in- dividual efforts, to accomplish their general task, never impeding each other by useless assistance, each taking a particular department, and each knowing its own duties. We may, however, not the less admire the solitary wasp or bee, who begins and finishes every part of its des- tined work ; just as we admire the ingenious mechanic who perfects something useful or ornamental entirely by the labour of his own hands, — whether he be the patient Chinese carver, who cuts the most elaborately decorated boxes out of a solid piece of ivory, or the turner of Europe, who produces every variety of elegant form by the skilful application of the simplest means. Our island abounds with many varieties of solitary wasps and bees ; and their nests may therefore be easily discovered by those who, in the proper sciisons, are de- sirous of observing the peculiarities of their architecture. MASO^'-BEES. 31 Mason- Wasps. In September, 1828, a common species of solitary mason-wasp ( Odynerus^ LATR.).was observed by us ( J. R.) Odynerus. — Natural size. on the east wall of a house at Lee, in Kent, very busy in excavating a hole in one of the bricks, about five feet from the ground. Whether there might not have been an accidental hole in the brick, before the wasp com- menced her labours, is unknown, as she had made con- siderable progress in the work when first observed ; but the brick was one of the hardest of the yellow sort made in this neighbourhood. The most remarkable circum- stance in the process of hewing into the brick, was the care of the insect in removing to a distance the fragments which from time to time she succeeded in detaching. It did not appear to suit her design to wear down the brick, particle by particle, as the furniture beetle (Anobiwn pertinax) does in making its pin-hole galleries in old wood. Our wasp-architeet, on the contrary, by means of her strong ^ranc/ia«^-toothed jaws, severed a piece usually about the bigness of a mustard-seed. It might have been supposed that these fragments would have been tossed out of the hole as the work proceeded, with- out further concern ; as the mole tosses above ground the earth which has been cleared out of its subterranean gallery. The wasp was of a different opinion ; for it was possible that a heap of brick chips, at the bottom of the wall, might lead to the discovery of her nest by some of her enemies, pai'ticularly by one or other of the nume- rous tribe of what are called ichneumon flies. This name is given to them, from the similarity of their habit of destroying eggs, to that of the little animal which proves so formidable an enemy to the multiplication of 32 IXSECT ARCHITECTURE. Mandibles — Jaws of Mason-Wasp,— Greatly magnified. the crocodile of Egypt. They may be also denominated cuckoo flies, because, like that bird, they thrust their egg into the nest of another species. These flies are con- tinually prowling about and prying into every corner, to find, by stealth, a nidus for their eggs. It might have been some such consideration as this which induced the wasp to carry oft' the fragments as they were successively detached. That concealment was the motive, indeecl, was proved ; for one of the fragments which fell out of the hole by accident, she immediately sought for at the bottom of the wall, and carried off" like the rest. It was no easy matter to get out one of the fragments, as may readily be conceived when the size of the insect is com- pared with that of the entrance, of which this (^) is the exact size, as taken from the impression of a bit of dough upon the hole when finished. It was only by seizing the fragment with her jaws, and retreating back- wards, that the matter could be accomplished; though, after the interior of the excavation was barely large enough to admit of her turning round, she more than once attempted to make her exit head-foremost, but always unsuccessfully. The weight of the fragments removed did not appear to impede her flight, and she generally returned to her task in about two or three minutes. Within two days the excavation was completed ; but it required two other days to line it with a coating of clay, to deposit the eggs, two in number, and, no doubt, to imprison a few live spiders or caterpillars, for the MASOX-BEES. young when hatched — a process which was first observed by Ray and Willughby,* but which has since been fre- quently ascertained. In the present instance, this pecu- liarity was not seen ; but the little architect was detected in closing up the entrance, which was formed of a layer of clay more than double the thickness of the interior lining. In November following, we hewed away the brick around this nest, and found the whole excavation was rather less than an inch in depth. Notwithstanding all the precautions of the careful parent to conceal her nest, it was found out by one of the cuckoo flies (laclnna larvarum?) — probably a com- mon species very similar to the house-fly, but rather Cuckoo.Fly — (Tachina larvarum ?) — Natural size. larger, which deposited an egg there; and the grub hatched from it, after devouring one of the w asp-grubs, Mason- Wasp's Nest and Cocoons.— About one-third the natural size. formed itself a cocoon («), as did the other undevoured grub of the wasp (b). Both awaited the return of sum- mer to change into winged insects, burst their cerements, and proceed as their parents did. VOL. I. * Ray, Hist. Insect.. 251. 84 INSECT ARCHITECTURE. Mason-Wasp— (Odyncrus mararius). — Natural size. Another mason-wasp {Odynerus murarius, Latr.), differing little in appearance from the former, may often be seen frequenting sandy banks exposed to the sun, and constructing its singular burrows. The sort of sand-bank which it selects is hard and compact ; and though this may be more difficult to penetrate, the walls are not liable to fall down upon the little miner. In such a bank, the mason-wasp bores a tubular gallery two or three inches deep. The sand upon which Reaumur found some of these wasps at work was almost as hard as stone, and yielded with difficulty to his nail ; but the wasps dug into it with ease, having recourse, as he ascertained, to the ingenious device of moistening it by letting fall two or three drops of fluid from their mouth, which ren- dered the mass ductile, and the separation of the grains easy to the double pickaxe of the little pioneers. When this wasp has detached a few grains of the moistened sand, it kneads them together into a pellet about the size of one of the seeds of a gooseberry. With the first pellet which it detaches, it lays the foundation of a round tower, as an outwork, immediately over the mouth of its nest. Every pellet which it afterwards carries off" from the interior is added to the wall of this outer round tower, which advances in height as the hole in the sand increases in depth. Every two or three minutes, however, during these operations, it takes a short excursion, for the purpose, probably, of replenish- ing its store of fluid wherewith to moisten the sand. Yet so little time is lost, that Reaumur has seen a mason-wasp dig in an hour a hole the length of its body, and at the same time build as much of its round tower. For the greater part of its height this round tower is perpen- MASON-3EES. 35 Nests, Sec, of Mason-Wasps.— About half the natural size. a, Tlie tower of the nest ; b, the entrance after the tower is removed ; c,the cell; rf.the cell, with a roll of caterpillars prepared for the larva. dicular ; but towards the summit it bends into a curve, corresponding to the bend of the insect's body, which, in all cases of insect architecture, is the model followed. The pellets which form the walls of the tower are not very nicely joined, and numerous vacuities are left be- tween them, giving it the appearance of fillagree work. That it should be thus slightly built is not surprising, for it is intended as a temporary structure for protecting the insect while it is excavating its hole ; and as a pile of materials, well arranged and ready at hand, for the completion of the interior building, — in the same way that workmen make a regular pile of bricks near the spot where they ai'e going to build. This seems, in fact, to be the main design of the tower, which is taken down as expeditiously as it had been reared. Reaumur thinks that, by piling in the sand which has previously been dug out, the wasp intends to guard his progeny for a time from being exposed to the too violent heat of the sun ; and he has even sometimes seen that there were not suf- ficient materials in the tower, in which case the wasp had c2 36 IKSECT ARCHITECTURE. recourse to the rubbish she had thrown out after the tower was completed. By raising a tower of the mate- rials which she excavates, the wasp produces the same shelter from external heat as a human creature would who chose to inhabit a deep cellar of a high house. She further protects her progeny from the ichneumon fly, as the engineer constructs an outwork to render more diffi- cult the approach of an enemy to the citadel. Reaumur has seen this indefatigable enemy of the wasp peep into the mouth of the tower, and then retreat, apparently frightened at the depth of the cell which he was anxious to invade. The mason-wasp docs not furnish the cell she has thus constructed with pollen * and honey, like the solitar}^ bees, but with living caterpillars, and these always of the same species — being of a green colour, and without feet. She fixes the caterpillars together in a spiral column : they cannot alter their position, although they remain alive. They are an easy prey to their smaller enemy ; and when the grub has eaten them all up, it spins a case, and is transformed into a pupa, which afterwards becomes a wasp. The number of caterpillars which is thus found in the lower cavity of the mason- wasp's nest is ordinarily from ten to twelve. The mother is careful to lay in the exact quantity of provision which is necessary to the growth of the grub before he quits his retreat. He works through his store till his increase in this state is perfected, and he is on the point of undergoing a change into another state, in which he requires no food. The careful purveyor, cruel indeed in her choice of a supi)ly, but not the less directed by an unerring instinct, selects such caterpillars as she is conscious have completed their growth, and will remain thus imprisoned without increase or corruption till their destroyer has gradually satisfied the necessities of his being. *' All that the worm of the wasp," says Reaumur, " las to do in his nest, from his birth to his transformation, is to eat." There is another species of wasp which does not at once enclose * The prolific po;vdcr of flj.vers. MASOX-BEES. 37 in its nest all the sustenance which its larva will require before transformation, but which from time to time im- prisons a living caterpillar, and when that is consumed opens the nest and introduces another.* Masox-Bees. It would not be easy to find a more simple, and, at the same time, ingenious specimen of insect architecture than the nests of those species of solitary bees which have been justly called mason-bees {JHegachile, La- tueille). Reaumur, who was struck by the analogies between the proceedings of insects and human arts, first gave to bees, wasps, and caterpillars those names which indicate the character of their labours ; and which, though they may be considered a little fanciful, are at least calculated to arrest the attention. The nests of mason-bees are constructed of various materials ; some with sand, some with earth mixed with chalk, and some with a mixture of earthy substances and wood. On the north-east wall of Greenwich Park, facing the road, and about four feet from the ground, we disco- vered (J. R.), December 10th, 1828, the nest of a mason- bco, formed in the perpendicular line of cement between two bricks. Externally there Avas an irregular cake of dry mud, precisely as if a handful of wet road-stuff" had been taken from a cart-rut and thrown against the wall ; though, upon closer inspection, the cake contained more small stones than usually occur in the mud of the adja- cent cart-ruts. We should in fact have passed it by with- Mason-Eee— (^*jt/jc>j)/jcr« retusn). — Natural size. * Bonnet, Contemplation, &c. 1. xii. c. 41. 38 INSECT ARCHITECTURE. out notice had there not been a circular hole on one side of it, indicating the perforation of some insect. This Exterior Wall of Mason-Bee's Nest. hole was found to be the orifice of a cell about an inch deep, exactly of the form and size of a lady's thimble, finely polished, and of the colour of plaster of Paris, but stained in various places with yellow. This cell was empty ; but. upon removing the cake of of mud, we discovered another cell, separated from the former by a partition about a quarter of an inch thick, and in it a living bee, from which the preceding figure was drawn, and which, as we supposed, had just changed from the pupa to the winged state, in consequence of the uncommon* mildness of the weather. The one which had occupied the adjacent cell had, no doubt, already dug its way out of its prison, and would probably fall a victim to the first frost. 5» ^V!' |fl Cells of a Mason-Bee (/!n'/.ophora rcttisa). —One-th'nd the natural size. MASOX-BEES. 31) Our nest contained only two cells — perhaps from there not being room between the bricks lor more. An interesting account is given by Reaumur of another mason-bee (Megaddle miirwia), not a native of Britain, selecting earthy sand, grain by grain ; her gluing a mass of these together with saliva, and building with them her cells from the foundation. But the cells of the Green- wich Park nest were apparently composed of the mortar of the brick wall ; though the external covering seems to have been constructed as Reaumur describes his nest, with the occasional addition of small stones. About the middle of May, 1829, we discovered the mine from which all the various species of mason-bees in the vicinity seemed to derive materials for their nests. (J.R.) It was a bank of brown clay, facing the east, and close by the margin of the river Ravensbourn, at Lee, in Kent. The frequent resort of the bees to this spot attracted the attention of some workmen, who, deceived by their re- semblance to wasps, pointed it out as a wasps' nest ; though they were not a little surprised to see so numerous a colony at this early season. As the bees had dug a hole in the bank, where they were incessantly entering and reappearing, we were of opinion that they were a peculiar sort of the social earth-bees (Bomhi). On ap- proaching the spot, however, we remarked that the bees were not alarmed, and manifested none of the irritation usual in such cases, the consequence of jealous affection for their young. This led us to observe their operations more minutely ; and we soon discovered that on issuing from the hole each bee carried out in its mandibles a piece of clay. Still supposing that they were social earth- bees, we concluded that they were busy excavating a hollow for their nest, and carrying off the refuse to pre- vent discovery. The mouth of the hole was overhung, and partly concealed, by a large pebble. This we re- moved, and widened the entrance of the hole, intending to dig down and ascertain the state of the operations ; but we soon found that it was of small depth. The bees, being scared away, began scooping out clay from another hole about a yard distant from the first. Upon our with- 40 IXSECT AKCHITECTURE. drawing a few feet from the first hole, they returned thither in preference, and continued assiduously digging and removing the clay. It became obvious, therefore, from their thus changing place, that they were not con- structing a nest, but merely quarrying for clay as a build- ing material. By catching one of the bees (^Osmia hicornis) when it was loaded with its burden, we ascer- tained that the clay was not only carefully kneaded, but was also more moist than the mass from which it had been taken. The bee, therefore, in preparing the pellet, which was nearly as large as a garden pea, had moistened it with its saliva, or some similar fluid, to render it, we may suppose, more tenacious, and better fitted for build- ing. The reason of their digging a hole, instead of taking clay indiscriminately from the bank, appeared to be for the purpose of economizing their saliva, as the weather was dry, and the clay at the surface was parched and hard. It must have been this circumstance which induced them to prefer digging a hole, as it were, in concert, though each of them had to build a separate nest. The distance to which they carried the clay was pro- bably considerable, as there was no wall near, in the direc- tion they all flew towards, upon which they could build ; and in the same direction also, it is worthy of remark, they could have procured much nearer the very same sort of clay. Whatever might be the cause of their pre- ference, we could not but admire their extraordinary in- dustry. It did not require more than half a minute to knead one of the pellets of clay ; and, from their fre- quent returns, probably not more than five minutes to carry it to the nest, and apply it where wanted. From the dryness of the weather, indeed, it was indis- pensable for them to work rapidly, otherwise the clay could not have been made to hold together. The extent of the whole labour of forming a single nest may be imagined, if we estimate that it must take several hun- dred pellets of clay for its completion. If a bee work fourteen or fifteen hours a day, therefore, carrying ten or twelve pellets to its nest every hour, it will be able to MA SOX- BEES. 41 finish the structure in about two or three days ; allowing some hours of extra time for the more nice workmanshij) of the cells in which the eggs are to be deposited, and the young grubs reared. That the construction of such a nest is not a merely agreeable exercise to the mason-bee has been sufficiently proved by M. Du Hamel. He has observed a bee \Megachile murarid) less careful to perform the neces- sary labour for the protection of her offspring than these we have described, but not less desirous of obtaining this protection, attempt to usurp the nest which another had formed. A fierce battle was invariably the conse- quence of this attempt ; for the true mistress would never give place to the intruder. The motive for the injustice and the resistance was an indisposition to further labour. The trial of strength was probably, sometimes, of as little use in establishing the right as it is amongst mankind ; and the proper owner, exhausted by her efforts, had doubtless often to surrender to the dishonest usurper. The account which Reaumur has given of the opera- tions of this class of bees differs considerably from that which we have here detailed ; from the species being different, or from his bees not having been able to procure moist clay. On the contrary, sand was the chief mate- rial used by the mason-bees {Megachile muraria) ; which they had the patience to select from the walks of a garden, and knead into a paste or mortar, adapted to their building. They had consequently to expend a much greater quantity of saliva than our bees {^Osmia bicoiTiis), which worked with moist clay. Reaumur, in- deed, ascertained that every individual grain of sand is moistened previous to its being joined to the pellet, iu order to make it adhere more effectually. The tenacity of the mass is besides rendered stronger, he tells us, by adding a proportion of earth or garden mould. In th's manner, a ball of imortar is formed, about the size of a small shot, and carried off to the nest. When the struc- ture of this is examined, it has all the appearance exter- nally of being composed of earth and small stones or • c 3 42 INSECT AECHITECTURE. gravel. The ancients, who were by no means accurate naturaUsts, having observed bees carrying pellets of earth and small stones, supposed that they employed these to add to their weight, in order to steady their flight when impeded by the wind. The nests thus constructed appear to have been more durable edifices than those which have fallen under our observation ; — for Reaumur says they were harder than many sorts of stone, and could scarcely be penetrated with a knife. Ours, on the contrary, do not seem harder than a piece of sun-baked clay, and by no means so hard as brick. One circumstance appeared inexplicable to Reaumur and his friend Du Hamel, who studied the operations of these insects in concert. After taking a portion of sand from one part of the garden- walk, the bees usually took another portion from a spot almost twenty and sometimes a hundred paces off, though the sand, so far as could be judged by close examination, was precisely the same in the two places. We should be disposed to refer this more to the restless character of the insect, than to any difference in the sand. We have observed a wasp pai'ing the outside of a plank, for mate- rials to form its nest ; and though the plank was as uni- form in the qualities of its surface, nay, probably more so than the sand could be, the wasp fidgeted about, nibbling a fibre from one, and a fibre from another portion, till enough w'as procured for one load. In the same way, the whole tribe of wasps and bees flit rest- lessly from flower to flower, not unfrequently revisiting the same blossom, again and again, within a few seconds. It appears to us, indeed, to be far from improbable, that this very restlessness and irritability may be one of the springs of their unceasing industry. By observing, with some care, the bees which we found digging the clay, we discovered one of them ( Osmia hicornis) at work upon a nest, about a gunshot from the bank. The place it had chosen was the inner wall of a coal-house, facing the south-west, the brick- work of which was but roughly finished. In an upright interstice of half an inch in width, between two of the MASOX-BEES. 43 bricks, we found the little architect assiduously building its walls. The bricklayer's mortar had either partly fallen out, or been removed by the bee, who had com- menced building at the lower end, and did not build downwards, as the social wasps construct their cells. The very different behaviour of the insect here, and at the quarry, struck us as not a little remarkable. When digging and preparing the clay, our approach, however near, produced no alarm ; the work went on as if we had been at a distance ; and though we were standing close to the hole, this did not scare away any of the bees upon their arrival to procure a fresh load. But if we stood near the nest, or even in the way by which the bee flew to it, she turned back or made a wide circuit immediately, as if afraid to betray the site of her domicile. We even observed her turning back, when we were so distant that it could not reasonably be supposed she was jealous of us ; but probably she had detected some prowling insect depredator, tracking her flight with designs upon her provision for her future progeny. We imagined we could perceive not a little art in her jealous caution, for she would alight on the tiles as if to rest herself; and even when she had entered the coal-house, she did not go directly to her nest, but again rested on a shelf, and at other times pretended to examine several crevices in the wall, at some distance from the nest. But when there was nothing to alarm her, she flew directly to the spot, and began eagerly to add to the building. It is iu instances such as these, which exhibit the adaptation of instinct to circumstances, that our reason finds the greatest difficulty in explaining the governing principle of the minds of the inferior animals. The mason-bee makes her nest by an invariable rule ; the model is in her mind, as it has been in the mind of her race from their first creation : they have learnt nothing by experience. But the mode in which they accomplish this task varies according to the situations in which they are placed. They appear to have a glimmering of 44 IXSECT AECniTECTL'SE. reason, employed as an accessary and instrument of their instinct. The structure, when finished, consisted of a wall of clay supported by two contiguous bricks, enclosing six chambers, within each of which a mass of pollen, rather larger than a cherry-stone, was deposited, together with an egg, from which in due time a grub was hatched. Contrary to what has been recorded by preceding natu- ralists, with respect to other mason-bees, we found the cells in this instance quite parallel and perpendicular ; but it may also be remarked, that the bee itself was a Cells of Mason Bees, built, in the first and second figures, by Osmia bicovTiis between bricks, and in the third, by Megachile muraria in the fluting of an old pilaster. — About half the natural size. species altogether different from the one which we have described above as the Anthophora retusa, and agreed with the figure of the one we caught quarrying the clay — (Os7nia hicornis). There was one circumstance attending the proceedings of this mason-bee which struck us not a little, though we (ould not exj>lain it to our own satisfaction. Every time she left her nest for the purpose of procuring a fresh supply of materials, she paid a regular visit to the blos- soms of a lilac tree which grew near. Had these blossoms afibrded a supply of pollen, with Avhich she could have replenished her cells, we could have easily MASON-BEES. 45 understood her design ; but the pollen of the lilac is not suitable for this purpose, and that she had never used it was proved by all the pollen in the cells being yellow, whereas that of the lilac is of the same pale, purple colour as the flowers. Besides, she did not return im- mediately from the lilac tree to the building, but always went for a load of clay. There seemed to us, therefore, to be only two ways to explain the circumstance : — she must either have applied to the lilac blossoms to obtain a refreshment of honey, or to procure glutinous materials to mix with the clay. Vv hen employed upon the building itself, the bee ex- hibited the restless disposition peculiar to most hymeno- pterous* insects ; for she did not go on with one particular portion of her wall, but ran about from place to place every time she came to work. At first, when we saw her running from the bottom to the top of her building, we naturally imagined that she went up for some of the bricklayer's mortar to mix with her own materials ; but upon minutely examining the walls afterwards, no lime could be discovered in their structure similar to that which was apparent in the nest found in the wall of Greenwich Park. Reaumur mentions another sort of mason-bee, which selects a small cavity in a stone, in which she forms her Mason-Bee and Nest, from Reaumur. * The fifth order of Linnaeus ; insects with four transparent veined win^s. 46 INSECT ARCHITECTTKE. nest of garden mould moistened with gluten, and after- wards closes the hole with the same material. Mixing-Bees. A very small sort of bees (Ajidrence), many of them not larger than a house-fly, dig in the ground tubular galleries little wider than the diameter of their own bodies. Samouelle says, that all of them seem to prefer a southern aspect ; but we have found them in banks facing the east, and even the north. Immediately above the spot where we have described the mason-bees quar- rying the cla}'^, we observed several holes, about the dia- meter of the stalk of a tobacco-pipe, into which those little bees were seen passing. The clay here was very hard ; and on passing a straw into the hole as a director, and digging down for six or eight inches, a very smooth circular gallery was found, terminating in a thimble- shaped horizontal chamber, almost at right angles to the entrance and nearh^ twice as wide. In this chamber there was a ball of blight yellow pollen, as round as a garden pea, and rather larger, upon which a small white grub was feeding ; and to which the mother bee had been adding, as she had just entered a minute before with her thighs loaded with pollen. That it was not the male, the load of pollen determined ; for the male has no apparatus for collecting or transporting it. The Cell of Minini,'-Kee (Andrena). — About half the natural size. whole labour of digging the nest and providing food for the young is performed by the female. The females of the solitary bees have no assistance in their tasks. The MIX I>G -BEES. 47 males are idle ; and the females are unprovided with la- bourers, such as the queens of the hive command. Reaumur mentions that the bees of this sort, whose operations he had observed, piled up at the entrance of their galleries the earth which they had scooped out from the interior ; and when the grub was hatched, and pro- perly provided with food, the earth was again employed to close up the passage, in order to prevent the intrusion of ants, ichneumon-flies, or other depredators. In those which we have observed, this was not the case ; but every species diflcrs from another in some little pecu- liarity, though they agree in the general principles of their operations. 48 U;SECT ARCHITECTUKK. CHAPTER III. Carpeuter-Bees; Carpenter- Wasps; Upbolsterer-Bees. ' CARP£^'TER-BEES. Among the solitary bees are several British species which come under that class called carpenter-bees byM. Reaumur, from the circumstance of their working in wood, as the mason-bees work in stone. We have fre- quently witnessed the operations of these ingenious little workei-s, who are particularly partial to posts, palings, and the wood-work of houses which has become soft by beginning to decay. Wood actually decayed, or afiected by dry-rot, they seem to reject as unfit for their pur- poses ; but they make no objections to any hole pre- viously drilled, provided it be not too large ; and, like the mason-bees, they not unfrequently take possession of an old nest, a few repairs being all that in this case is necessary. When a new nest is to be constructed, the bee pro- ceeds to chisel sufficient space for it out of the wood with her jaws. We say lier, becaiLse the task in this instance, as in most others of solitary bees and wasps, devolves solely upon the female, the male taking no concern in the affair, and probably being altogether ignorant that such a work is going forward. It is, at least, certain that the male is never seen giving his assistance, and he seldom, if ever, approaches the neighbourhood. The female carpenter-bee has a task to perform no less arduous than the mason-bee ; for though the wood may be tolerably soft, she can only cut out a very small portion at a time. The successive portions which she gnaws off may be readily ascertained by an observer, as she carries them away from the place. In giving the CARPENTER-BEES. 49 history of a mason-wasp {Odynerns), at page 27, we remarked the care with which she carried to a distance little fragments of brick, which she detached in the pro- gress of excavation. We have recently watched a pre- cisely similar procedure in the instance of a carpenter- bee forming a cell in a wooden post. (J. R.) The only difference was, that the bee did not fly so far away with her fragments of wood as the wasp did ; but she varied the direction of her flight every time : and we could observe, that after dropping the chip of wood which she had carried off, she did not return in a direct line to her nest, but made a circuit of some extent before wheeling round to go back. On observing the proceedings of this carpenter-bee next day, we found her coming in with balls of pollen on her thighs ; and on tracing her from the nest into the adjacent garden, we saw her visiting every flower which Mas likely to yield her a supply of pollen for her future progeny. This was not all : we subsequently saw her taking the direction of the clay-quarry frequented by the mason-bees, as we have mentioned in page 35, where we recognised her loading herself with a pellet of clay, and carrying it into her cell in the wooden post. We ob- served her alternating this labour for several days, at one time carrying clay, and at another pollen ; till at length she completed her task, and closed the entrance with a barricado of clay, to prevent the intrusion of any insecti- vorous depredator, who might make prey of her young ; or of some prying parasite, who might introduce its own eggs into the nest she had tiiken so much trouble to construct. Some days after it was finished, we cut into the post, and exposed this nest to view. It consisted of six cells of a somewhat square shape, the wood forming the lateral walls ; and each was separated from the one adjacent by a partition of clay, of the thickness of a playing card. The wood was not lined with any extraneous substance, but was worked as smooth as if it had been chiselled by a joiner. There were five cells, arranged in a very sin- CO INSIiCT ARCHITECTLEJi. Cells of Carpenter-Bees, excavated in an old post. In fig. A the cells contain the young grubs ; in fig. B the cells are empty. Both figures are shown in section, and about half their natural size. gular manner — two being almost horizontal, two perpen- dicular, and one oblique. The depth to which the wood was excavated in this instance, was considerably less than what we have ob- served in other species which dig perpendicular galleries several inches deep in posts and garden-seats ; and they are inferior in ingenuity to the carpentry of a bee de- scribed by Reaumur (^Xylocopa violacea), which has not been ascertained to be a native of Britain, though a single indigenous species of the genus has been doubtingly mentioned, and is figured by Kirby and Spence, in their valuable * Monographia.' If it ever be found here, its large size and beautiful violet-coloured wings will render mistakes impossible. The violet carpenter-bee usually selects an upright piece of wood, into which she bores obliquely for about an inch ; and then, changing the direction, works per- pendicularly, and parallel to the sides of the wood, for twelve or fifteen inches, and half an inch in breadth. Sometimes the bee is contented with one or two of these excavations ; at other times, when the wood is adapted CARPENTER-BEES. 51 to it, she scoops out three or four — a task which some- times requires several weeks of incessant labour. The tunnel in the wood, however, is only one part of the work ; for the little architect has afterwards to divide the whole into cells, somewhat less than an inch in depth. A represents a part of an espalier prop, tunnelled in several places by the violet carpenter-tee: the stick is split, and shews the nests and passages by which they are approached. B, a portion of the prop, half the natural size. C, a piece of thin stick, pierced by the carpenter- bee, and split, to shew the nests. D, Perspective view of one of the partitions. E, Carpenter-bee {Xylocopa viulacea). F, Teeth of the carpenter tee, greatly magnified ; a, the upper side ; b, the lower side. 52 INSECT ARCHITECTURE. It is necessary, for the proper growth of her progeny, that each should be separated from the other, and be provided with adequate food. She knows, most exactly, the quantity of food which each grub will require, dur- ing its growth ; and she therefore does not hesitate to cut it off from any additional supply. In constructing her cells, she does not employ clay, like the bee which we have mentioned above, but the sawdust, if we may call it so, which she has collected in gnawing out the gallery. It would not, therefore, have suited her design to scatter this about, as our carpenter-bee did. The violet-bee, on the contrary, collects her gnawings into a little store-heap for future use, at a short distance from her nest. She proceeds thus : — At the bottom of her excavation she deposits an egg, and over it fills a space nearly an inch high with the pollen of flowTrs, made into a paste with honey. She then covers this over with a ceiling composed of cemented sawdust, w hich also serves for the floor of the next chamber above it. For this purpose, she cements round a wall a ring of wood chips taken from her store-heap ; and within this ring forms another, gradually contracting the diameter till she has constructed a circular plate, about the thickness of a crown-piece, and of considerable hardness. This plate of course exhibits concentric circles, somewhat similar to the annual circles in the cross section of a tree. In the same manner she proceeds till she has completed ten or twelve cells ; and then she closes the main entrance with a barrier of similar materials. ' Let us compare the progress of this little joiner with a human artisan — one who has been long practised in his trade, and has the most perfect and complicated tools for his assistance. The bee has learnt nothing by prac- tice ; she makes her nest but once in her life, but it is then as complete and finished as if she had made a thou- sand. She has no pattern before her — but the Architect of all things has impressed a plan upon her mind, which she can realize without scale or compasses. Her tw'o sharp teeth are the only tools with which she is provided for her laborious work ; and yet she bores a tunnel, CAKPEJJTEa-BEES. 63 twelve times the length of her own body, with greater ease than the workman who bores into the earth for water, with his apparatus of augurs adapted to every soil. Her tunnel is clean and regular ; she leaves no chips at the bottom, for she is provident of her materials. Fur- ther, she has an exquisite piece of joinery to perform when her ruder labour is accomplished. The patient bee works her rings from the circumference to the centre, and she produces a shelf, united with such care with her natural glue, that a number of fragments are as solid as one piece. The violet carpenter-bee, as may be expected, occu- pies several weeks in these complicated labours ; and during that period she is gradually depositing her eggs, each of which is successively to become a grub, a pupa, and a perfect bee. It is obvious, therefore, as she does not lay all her eggs in the same place — as each is sepa- rated from the other by a laborious process — that the egg which is first laid will be the earliest hatched ; and that the first perfect insect, being older than its fellows in the same tunnel, will strive to make its escape sooner, and so on of the rest. The careful mother provides for this contingency. She makes a lateral opening at the bottom of the cells ; for the teeth of the young bees would not be strong enough to pierce the outer wood, though they can remove the cemented rings of sawdust in the interior. Reaumur observed these holes, in se- veral cases ; and he further noticed another external opening opposite to the middle cell, which he supposed was formed, in the first instance, to shorten the distance for the removal of the fragments of wood in the lower half of the building. That bees of similar habits, if not the same species as the violet-bee, are indigenous to this country, is proved by Grew, who mentions, in his ' Rarities of Gresham College,' having found a series of such cells in the middle of the pith of an elder branch, in which they were placed lengthwise, one after another, with a thin boundary be- tween each. As he does not, however, tell us that he 54 INSECT ARCHITECTURE. was acquainted with the insect which constructed these, it might as probably be allied to the Ceratina albilabris, of which Spinola has given so interesting an account in the ' Annales du Museum d'Histoire Naturelle ' (x. 236). This noble and learned naturalist tells us, that one evening he perceived a female ceratina alight on the branch of a bramble, partly withered, and of which the extremity had been broken ; and, after resting a moment, suddenly disappear. On detaching the branch, he found that it was perforated, and that the insect was in the very act of excavating a nidus for her eggs. He forthwith gathered a bundle of branches, both of the bramble and the wild-rose, similarly perforated, and took them home to examine them at leisure. Upon inspection, he found that the nests were furnished like those of the same tribe, with balls of pollen kneaded with honey, as a pro- vision for the grubs. The female ceratina selects a branch of the bramble or wild-rose which has been accidentally broken, and digs into the pith only, leaving the wood and bark un- touched. Her mandibles, indeed, are not adapted for gnawing wood ; and, accordingly, he found instances in which she could not finish her nest in branches of the wild-rose, where the pith M'as not of sufficient diameter. The insect usually makes her perforation a foot in depth, and divides this into eight, nine, or even twelve cells, each about five lines long, and separated by par- titions formed by the gnawings of the pith, cemented by honey, or some similar glutinous fluid, much in the same manner with the xylocopa violacea, which we have already described. Carpenter- Wasps. As there are mason-wasps similar in economy to mason-bees, so are there solitary carpenter-wasps which dig galleries in timber, and partition them out into several cells by means of the gnawings of the wood which they have detached. This sort of wasp is of the genus JEitmenes. The wood selected is generally such as is soft, or in a state of decay ; and the hole which is dug tPHOJ.STERER-BEEr. 66 •"V B represent sections of old wooden posts, with the cells of the carpenter-wasp. In tig. A the young grubs are shewn feeding on the insects placed there for their support by the parent wasp. The cells in fig. B contain cocoons. C, carpenter-wasp, natural size. D, cocoon of a carpenter-wasp, composed of sawdust and wings of insects. in it is much less neat and regular than i^that of the carpenter-bees, while the division of the ^chambers is nothing more than the rubbish produced during the ex- cavation. The provision which is made for the grub consists of flics or gnats piled into the chamber, but without the nice order remarkable in the spiral columns of green caterpillars provided by the mason- wasp (^Odynenis murariiis). The most remarkable circumstance is, that in some of the species, when the grub is about to go into the pupa statd, it spins a case (a cocoon), into' which it interweaves the wings of the flies whose bodies it has previously devoured. In other species, the gnawings of the wood are employed in a similar manner. Upholsterer-Bees. In another part of this volume we shall see how certain caterpillars construct abodes for themselves, by cutting off portions of the leaves or bark of plants, and uniting them by means of silk into a uniform and com- 66 INSECT ARCKITECTURE. pact texture ; but this scarcely appears so wonderful as the prospective labours of some species of bees for the lodgment of their progeny. We allude to the solitary bees, known by the name of the leaf-cutting bees, but which may be denominated more generally iipholsteier- bees, as there are some of them which use other materials beside leaves. One species of our little upholsterers has been called the poppy -bee (Osniia papaver is, Latb.), from its se- lecting the scarlet petals of the poppy as tapestry for its cells. Kirby and Spence express their doubts whether it is indigenous to this country : we are almost certain that we have seen the nests in Scotland. (J. R.) At Largs, in Ayrshire, a beautiful sea-bathing village on the Firth of Clyde, in July, 1811, we found in a foot- path a great number of the cylindrical perforations of the poppy-bee. Reaumur remarked that the cells of this bee which he found at Bercy, were situated in a northern exposure, contrary to what he had remarked in the mason-bee, which prefers the south. The cells at Largs, however, were on an elevated bank, facing the south, near Sir Thomas Brisbane's observatory. With respect to exposure, indeed, no certain rule seems applicable ; for the nests of mason-bees which we found on the wall of Greenwich Park faced the north-east, and we have often found carpenter-bees make choice of a similar situ- ation. In one instance, we found carpenter-bees working indifferently on the north-east and south-west side of the same post. As we did not perceive any heaps of earth near the holes at Largs, we concluded that it must either have been carried, off piecemeal when they were dug, or that they were old holes re-occupied (a circumstance com- mon with bees), and that the rubbish had been trodden down by passengers. Reaumur, who so minutely de- scribes the subsequent operations of the bee, says nothing respecting its excavations. One of these holes is about three inches deep, gradually widening as it descends, till it assumes the form of a small Florence flask. The in- terior of this is rendered smooth, uniform, and polished, LPHOLSTERER-BEES. 57 in order to adapt it to the tapestry with M'hich it is in- tended to be hung, and which is the next step in the process. The material used for tapestry by the insect uphol- sterer is supplied by the flower-leaves of the scarlet field-poppy, from which she successively cuts off small pieces of an oval shape, seizes them between her legs, and convej'S them to the nest. She begins her work at the bottom, which she overlays with three or four leaves in thickness, and the sides have never less than two. ""When she finds that the piece she has brought is too large to fit the place intended, she cuts off what is super- fluous, and carries away the shreds. By cutting the fresh petal of a poppy with a pair of scissors, we may perceive the difficulty of keeping the piece free from wrinkles and shrivelling ; but the bee knows how to spread the pieces which she uses as smooth as glass. When she has in this manner hung the little chamber all around with this splendid scarlet tapestry, of which she is not sparmg, but extends it even beyond the en- trance, she then fills it with the pollen of flowers mixed with honey, to the height of about half an inch. In this magazine of provisions for her future progeny she lays an egg, and over it folds down the tapestry of poppy-petals from above. The upper part is then filled in with earth ; but Latreille says, he has observed more than one cell coriStructed in a single excavation. This may account for Reaumur's describing them as sometimes seven inches deep ; a circumstance which Latreille, however, thinks very surprising. It will, perhaps, be impossible ever to ascertain, be- yond a doubt, whether the tapestry-bee is led to select the brilliant petals of the poppy from their colour, or from any other quality they may possess, of softness or of warmth, for instance. Reaumur thinks that the large- ness, united with the flexibility of the poppy-leaves, de- termines her choice. Yet it is not improbable that her eye may be gratified by the appearance of her nest ; that she may possess a feeling of the beautiful in colour, and may look with complacency upon the delicate hangings VOL. I. D 58 INSECT AKCHITECTURE. of the apartment which she destines for her offspring. Why should not an insect be supposed to have a glim- mering of the value of ornament? How can we pro- nounce, from our limited notion of the mode in which the inferior animals think and act, that their gratifications are wholly bounded by the positive utility of the objects which surround them ? Why does a dog howl at the sound of a bugle, but because it offends his organ of hearing '? — and why, therefore, may not a bee feel glad- ness in the brilliant hues of her scarlet drapery, because they are grateful to her organs of sight ? All these little creatures work, probably, with more neatness and finish than is absolutely essential for comfort ; and this circum- stance alone would imply that they [have something of taste to exhibit, which produces to them a pleasurable emotion. The tapestry-bee is, however, content with ornament- ing the interior only of the nest which she forms for her progeny. She does not misplace her embellishments with the error of some human artists. She desires se- curity as well as elegance ; and, therefore, she leaves no external traces of her operations. Hers is not a mansion rich with columns and friezes without, but cold and un- furnished within, like the desolate palaces of Venice. She covers her tapestry quite round with the common earth ; and leaves her eggs enclosed in their poppy-case win a certainty that the outward show of her labours will attract no plunderer. The poppy-bee may be known by its being rather more than a third ,'of an inch long, of a black colour, studded on the head and back with reddish grey hairs ; the belly being grey and silky, and the rings margined with grey above, the second and third having an im- pressed transversal line. A species of solitary bee (Anthidium mamcatumj Fabricius), by no means uncommon with us, forms a nest of a peculiarly interesting structure. Kirby and Spence say, that it does not excavate holes, but makes choice of the cavities of old trees, key-holes, and similar localities 5 yet it is highly probable, we think, that it UPHOLSTERER-BEES. ' 59 may sometimes scoop out a suitable cavity when it cannot find one ; for its mandibles seem equally capable of this, with those of any of the carpenter or mason bees. Ce this as it may, the bee in question having selected a place suitably sheltered from the weather, and from the intrusion of depredators, proceeds to form her nest, the exterior walls of which she forms of the wool of pubescent plants, such as rose-campion (^Lychnis coro- nan'a), the quince {Pi/rus cydonia), cats-ears {Stachys lunata), &c. '* It is very pleasant," says Mr. White of Selborne, " to see with what address this insect strips off the down, running from the top to the bottom of the branch, and shaving it bare with all the dexterity of a hoop-shaver. When it has got a vast bundle, almost as large as itself, it flies away, holding it secure between its chin and its fore-legs." * The material is rolled up like a ribbon, and we possess a specimen in which one of these rolls still adheres to a rose-campion stem, the bee having been scared away before obtaining her load. The manner in which the cells of the nest are made seems not to be very clearly understood. M. Latreille says, that after constructing her nest of the down of quince-leaves, she deposits her eggs, together with a store of paste, formed of the pollen of flowers, for nourishing the_^' grubs. Kirby and Spence, on the other hand, tell us, that " the parent bee, after having con- structed her cells, laid an e^^ in each, and filled them with a store of suitable food, plasters them with a cover- ing of vermiform masses, apparently composed of honey and pollen ; and Raving done this, aware, long before Count Rumford's experiments, what materials conduct heat most slowly," she collects the down from woolly plants, and "sticks it upon the plaster that covers her cells, and thus closely envelops them with a warm coating of down, impervious to every change of temperature." *' From later observations," however, they are " inclined to think that these cells may possibly, as in the case of the humble-bee, be in fact formed by the larva previously * Naturalist's Calendar, p. 100. d2 60 INSECT ARCHITECTURE. to becoming a pupa, after having eaten the provision of pollen and honey with which the parent bee had sur- rounded it. The vermicular shape, however, of the masses with which the cases are surrounded, does not seem easily reconcileable with this supposition, unless they are considered as the excrement of the larva." * Whether or not this second explanation is the true one, we have not the means of ascertaining ; but we are almost certain the first is incorrect, as it is contrary to the regular procedure of insects to begin with the inte- rior part of any structure, and M'ork outwards. We should imagine, then, that the down is first spread out into the form required, and afterwards plastered on the inside to keep it in form, when probably the grub spins the vermicular cells previous to its metamorphosis. It might prove interesting to investigate this more minutely ; and as the bee is by no means scarce in the neighbourhood of London, it might not be difficult for a careful observer to witness all the details of this singular architecture. Yet we have repeatedly endeavoured, but without success, to watch the bees, when loaded with down, to their nests. The bee may be readily known from its congeners, by its being about the size of the hive-bee, but more broad and flattened, blackish brown above, with a row of six yellow or white spots along each side of the rings, very like the rose-leaf cutter, and having the belly covered with yellowish brown hair, and the legs fringed with long hairs of a rather lighter colour. A common bee belonging to the family of upholsterers is called the rose-leaf cutter {Megacliile centimcnlarisj Latr.). The singularly ingenious habits of this bee have long attracted the attention of naturalists, but the most interesting description is given by Reaumur. So extraordinary does the construction of their nests appear, that a French gardener having dug up some, and be- lieving them to be the work of a magician, who had * Introduction to Eiitoniology, vol. i. p. 435, 5th edit. rPHOLSTERER- BEES . 61 placed them in his garden with evil intent, sent them to Paris to his master, for advice as to what should be done by way of exorcism. On applying to the Abbe Nollet, the owner of the garden was soon persuaded that the nests in question were the work of insects ; and M. Reaumur, to whom they were subsequently sent, found them to be the nests of one of the upholsterer-bees, and probably of the rose-leaf cutter, though the nests in question were made of the leaves of the mountain-ash (^Pyrus avcvparici). The rose-leaf cutter makes a cylindrical hole in a beaten pathway, for the sake of more consolidated earth (or in the cavities of walls or decayed wood), from six to ten inches deep, and does not throw the earth dug out Rose-leaf cutter Bees, and Nest lined with rose-leaves. 62 INSECT ARCHITECTURE. from it into a heap, like the Andrense,* In this she constructs several cells about an inch in length, shaped like a thimble, and made of cuttings of leaves (not petals), neatly folded together, the bottom of one thimble-shaped cell being inserted into the mouth of the one below it, and so on in succession. It is interesting to observe the manner in which this bee procures the materials for forming the tapestry of her cells. The leaf of the rose-tree seems to be that which she prefers, though she sometimes takes other sorts of leaves, particularly those with serrated margins, such as the birch, the perennial mercury (^Mercurialis perennis), mountain-ash, &c. She places herself upon the outer edge of the leaf which she has selected, so that its margin may pass between her legs. Turning her head towards the point, she commences near the foot- stalk, and with her mandibles cuts out a circular piece with as much expedition as we could do with a pair of scissors, and with more accuracy and neatness than could easily be done by us. As she proceeds, she keeps the cut portion between her legs so as not to impede her progress ; and using her body for a trammel^ as a car- penter would say, she cuts in a regular curved line. As she supports herself during the operation upon the por- tion of the leaf which she is detaching, it must be ob- vious, when it is nearly cut off, that the weight of her body might tear it away, so as to injure the accuracy of its curvilineal shape. To prevent any accident of this kind, as soon as she suspects that her weight might tear it, she poises herself on her wings, till she has completed the incision. It has been said, by naturalists, that this manoeuvre of poising herself on the wing, is to prevent her falling to the ground, when the piece gives way ; but as no winged insect requires to take any such pre- caution, our explanation is probably the true one. With the piece which she has thus cut out, held in a bent position perpendicularly to her body, she flies off to her nest, and fits it into the interior with the utmost * See p. 43. UPHOLSTERER-BEES. 63 neatness and ingenuity ; and, without employing any paste or glue, she trusts, as Reaumur ascertained, to the spring the leaf takes in drying, to retain it in its position. It requires from nine to twelve pieces of leaf to form one cell, as they are not always of precisely the same thickness. The interior surface of each cell consists of three pieces of leaf, of equal size, narrow at one end, but gradually widening at the other, where the width equals half the length. One side of each of the pieces is the serrated margin of the leaf from which it was cut, and this margin is always placed outermost, and the cut margin innermost. Like most insects, she begins with the exterior, commencing with a layer of tapestry, which is composed of three or four oval pieces, larger in di- mensions than the rest, adding a second and a third layer proportionately smaller. In forming these, she is care- ful not to place a joining opposite to a joining, but, with all the skill of a consummate artificer, lays the middle of each piece of leaf over the margins of the others, so as by this means both to cover and strengthen the junctions. By repeating this process, she sometimes forms a fourth or a fifth layer of leaves, taking care to bend the leaves at the narrow extremity or closed end of the cell, so as to bring them into a convex shape. When she has in this manner completed a cell, her next business is to replenish it with a store of honey and pollen, which, being chiefly collected from thistles, forms a beautiful rose-coloured conserve. In this she deposits a single egg, and then covers in the opening with three pieces of leaf, so exactly circular, that a pair of compasses could not define their margin with more accuracy. In this manner the industrious and ingenious upholsterer proceeds till the whole gallery is filled, the convex extremity of the one fitting into the open end of the next, and serving both as a basis and as the means of strengthening it. If, by any accident, the labour of these insects is interrupted or the edifice deranged, they exhibit astonishing perseverance in setting it again to rights. Insects, indeed, are not easily forced to abandon any Mork which they may have begun. -64 IXSECT ARCHITECTURE. The monkish legends tell us that St. Francis Xavier, walking one day in a garden, and seeing an insect, of the Mantis genus, moving along in its solemn way, holding up its two fore legs as in the act of devotion, desired it to sing the praises of God. The legend adds that the saint immediately heard the insect carol a fine canticle with a loud emphasis. We want no miraculous voice to record the wonders of the Almighty hand, when we re- gard the insect world. The little rose-leaf cutter, pur- suing her vvork with the nicest mathematical art — using no artificial instruments to form her ovals and her circles — knowing that the elastic property of the leaves will retain them in their position — making her nest of equal strength throughout, by the most rational adjustment of each distinct part — demands from us something more than mere wonder ; for such an exercise of instinctive ingenuity at once directs our admiration to the gi'eat Contriver, who has so admirably proportioned her know- ledge to her necessities. CARDER-BEES. CHAPTER IV. Carder-Bees ; Humble-Bees ; Social-Wasps. The bees and wasps, whose ingenious architecture we have ah'eady examined, are soHtary in their hibours. Those we are about to describe live in society. The perfection of the social state among this class of insects is certainly that of the hive-bees. They are the inha- bitants of a large city, where the arts are carried to a higher excellence than in small districts enjoying little communication of intelligence. But the iDees of the villages, if we may Ibllow up the parallel, are not with- out their interest. Such are those which are called car- der-bees and humble-bees. Carder-Bees. The nests of the bees which Reaumur denominates carders (^Boinbus muscorum, Latr.) are by no means un- common, and are well worth the study of the naturalist. During the hay harvest, they are frequently met with by mowers in the open fields and meadows ; but they may sometimes be discovered in hedge-banks, the borders of copses, or among moss-grown stones. The description of the mode of building adopted by this bee has been copied by most of our writers on insects from Reaumur ; though he is not a little severe on those who write without having ever had a single nest in their possession. We have been able to avoid such a reproach ; for we have now before us a very complete nest of carder-bees, which differs from those described by Reaumur, in being- made not of moss, but withered grass. With this exception, we find that his account agrees accurately with our own observations. (J. R.) The carder-bees select for their nests a shallow exca- D 3 66 INSECT ARCHITECTURE. A Fig. A represents two Carder-bees heckling moss for their nests, B, exterior view of the nest of the carder-bee. vation about half a foot in diameter; but when they cannot find one to suit their purpose, they undertake the Herculean task of digging one themselves. They cover this hollow with a dome of moss — sometimes, as we have ascertained, of withered grass. They make use, indeed, of whatever materials may be within their reach ; for they do not attempt to bring anything from a distance, not even when they are deprived of the greater portion by an experimental naturalist. Their only method of transporting materials to the building is by pushing them along the ground — the bee, for that purpose, working CARDER-BEES. 67 backwards, with its head turned from the nest. If there is only one bee engaged in this labour, as usually happens in the early spring, when a nest is founded by a solitary female who has outlived the winter, she transports her little bundles of moss or grass by successive backward pushes, till she gets them home. In the latter part of the season, when the hive is populous and can afford more hands, there is an ingenious division of this labour. A file of bees, to the number sometimes of half a dozen, is established, from the nest to the moss or grass which they intend to use, the heads of all the file of bees being turned from the nest and towards the material. The last bee of the file lays hold of some of the moss with her mandibles, disentangles it from the rest, and having carded it with her fore-legs into a sort of felt or small bundle, she pushes it under her body to the next bee, who passes it in the same manner to the next, and so on till it is brought to the border of the nest, — in the same way as we sometimes see sugar-loaves conveyed from a cart to a warehouse, by a file of porters throwing them from one to another. The elevation of the dome, which is all built from the interior, is from four to six inches above the level of the field. Beside the moss or grass, they frequently employ coarse wax to form the ceiling of the vault, for the pur- pose of keeping out rain, and preventing high winds from destroying it. Before this finishing is given to the nest, we have remarked, that on a fine sunshiny day the upper portion of the dome was opened to the extent of more than an inch, in order, we suppose, to forward the hatch- ing of the eggs in the interior ; but on the approach of night this was carefully covered in again. It was re- markable that the opening M'hich we have just mentioned was never used by the bees for either their entrance or their exit from the nest, though they were all at work there, and, of course, would have found it the readiest and easiest passage. But they invariably made their exit and their entrance through the covert-way or gallery which opens at the bottom of the nest, and, in some nests, is about a foot long and half an inch wide. This is, no 68 INSECT ARCHITECTURE. doubt, intended for concealment from field-mice, pole- cats, wasps, and other depredators. On removing a portion of the dome and bringing the interior of the structure into view, we find little of the architectural regularity so conspicuous in the combs of a common bee-hive : instead of this symmetry, there are only a few egg-shaped, dark-coloured cells, placed some- what irregularly, but approaching more to the horizontal than to the vertical position, and connected together with small amorphous * columns of brown wax. Sometimes there are two or three of these oval cells placed one above another, without anything to unite them. These cells are not, however, the workmanship of the old bees, but of their young grubs, who spin them when they are about to change into nymphs. But, from thcso cases, when they are spun, the enclosed insects have no means of escaping, and they depend for their liberation on the old bees gnawing off the covering, as is done also by ants in the same circumstances. The instinct with which they know the precise time when it is proper to do this is truly wonderful. It is no less so, that these cocoons are by no means useless when thus untenanted, for they subsequently serve for honey-pots, and are in- deed the only store-cells in the nest. For this purpose the edge of the cell is repaired and strengthened with a ring of wax. The true breeding-cells are contained in several amor- Breeding-Cells. * Shapeless. CARDER-BEES. 69 phous masses of brown-coloured wax, varying in dimen- sions, but of a somewhat flat and globular shape. On opening any of these, a number of eggs or grubs are found, on whose account the mother bee has collected the masses of wax, which also contain a supply of pollen moistened with honey, for their subsistence. Interior views of Carder-bee's Nest. The number of eggs or grubs found in one spheroid of wax varies from three to thirty, and the bees in a whole nest seldom exceed sixty. There are three sizes of bees, of which the females are the largest ; but neither 70 INSECT ARCHITECTURE. these nor the males are, as in the case of the hive-bee, -exempt from labour. The females, indeed, always found the nests, since they alone survive the winter, all the rest perishing with cold. In each nest, also, are several females, that live in harmony together. The carder-bees may be easily distinguished from their congeners (of the same genus), by being not unlike the colour of the withered moss with which they build their nests, having the fore part of their back a dull orange, and hinder part ringed with different shades of greyish yellow. They are not so large as the common humble-bee (JBombus terrestris, Latr.), but rather shorter and thicker in the body than the common hive- bee {Apis melhyica) . Lapidary- Bees. A bee still more common, perhaps, than the carder is the orange-lailed bee, or lapidary {Bombus lapldarid), readily known by its general black colour and reddish orange tail. It builds its nest sometimes in stony ground, but prefers a heap of stones such as are gathered off grass fields or are piled up near quarries. Unlike the carder, the lapidary carries to its nest bits of moss, which are very neatly arranged into a regular oval. These insects associate in their labours ; and they make honey with great industry. The individuals of a nest are more nu- merous than the carders, and likewise more pertinaciously vindictive. About two years ago we discovered a nest of these bees at Compton-Bassett, in Wiltshire, in the centre of a heap of limestone rubbish ; but owing to the brisk defensive warfare of their legionaries, we could not obtain a view of the interior. It was not even safe to approach within many yards of the place, and we do not exaggerate when we say that several of them pursued us most pertinaciously about a quarter of a mile. (J. R.) Humble-Bees. The common humble-bee (Bombus terresti'is) is pre- cisely similar in its economy to the two preceding species, with this difference, that it forms its nest underground SOCIAL-WASPS. 71 like the common wasp, in an excavated chamber, to which a winding passage leads, of from one to two feet, and of a diameter sufficient to allow of two bees passing. The cells have no covering beside the vault of the exca- vation and patches of coarse wax similar to that of the carder-bee. Social-Wasps. The nest of the common wasp ( Vespa indgaris) at- tracts more or less the attention of everybody ; but its interior architecture is not so well known as it deserves to be, for its singular ingenuit}'^, in which it rivals even that of the hive-bee {Apis melUfica). In their general eco- nomy the social or republican wasps closely resemble the humble-bee {Bomhus), every colony being founded by a single female who has survived the winter, to the rigours of which all her summer associates of males and working wasps uniformly fall victims. Nay, out of three hundred females which may be found in one vespiary, or wasp's nest, towards the close of autumn, scarcely ten or a dozen survive till the ensuing spring, at which season they awake from their hybernal lethargy, and begin with ardour the labours of colonization. It may be interesting to follow one of these mother wasps through her several operations, in which she merits more the praise of industry than the queen of a bee-hive, who does nothing, and never moves without a numerous train of obedient retainers, always ready to execute her commands and to do her homage. The mother wasp, on the contrary, is at first alone, and is obliged to perform every species of drudgery herself. Her first care, after being roused to activity by the re- turning warmth of the season, is to discover a place suitable for her intended colony ; and, accordingly, in the spring, w^asps may be seen prying into every hole of a hedge bank, particularly where field-mice have bur- rowed. Some authors report that she is partial to the forsaken galleries of the mole, but this does not accord with our observations, as we have never met with a single vespiai'y in any situation likely to have been fre- 72 INSECT ARCHITECTURE. quented by moles. But though we cannot assert the fact, we think it highly probable that the deserted nest of the field-mouse, which is not uncommon in hedge banks, may be sometimes appropritited by a mother wasp as an exca- vation convenient for her purpose. Yet, if she does make choice of the burrow of a field-mouse, it requires to be afterwards considerably enlarged in the interior chamber, and the entrance gallery very much narrowed. The desire of the wasp to save herself the labour of excavation, by forming her nest where other animals have burrowed, is not without a parallel in the actions of quadrupeds, and even of birds. In the splendid con- tinuation of Wilson's American Ornithology, by Charles L. Bonaparte (whose scientific pursuits have thrown round that name a beneficent lustre, pleasingly contrasted with his uncle's glory), there is an interesting example of this instinctive adoption of the labours of others. " In the trans-Mississippian territories of the United States, the burrowing-owl resides exclusively in the villages of the marmot, or prairie-dog, whose excavations are so commodious, as to render it unnecessary that the owl should dig for himself, as he is said to do where no bur- rowing animals exist.* The villages of the prairie-dog are very numerous and variable in their extent,— some- times covering only a few acres, and at others spreading over the surface of the country for miles together. They are composed of slightly-elevated mounds, having the form of a truncated cone, about two feet in width at the base, and seldom rising as high as eighteen inches from the surface of the soil. The entrance is placed either at the top or on the side, and the whole mound is beaten down externally, especially at the summit, re- sembling a much-used footpath. From the entrance, the passage into the mound descends vertically for one or two feet, and is thence continued obliquely downwards until it terminates in an apartment, within which the in- * The owl observed bj' Yieillot in St. Domingo digs itself a burrow two feet in depth, at the bottom of which it deposits its eggs upon a bed of moss. SOCIAL-WASPS. 73 dustrious prairie-dog constructs, on the approach of cold weather, a comfortable cell for his winter's sleep. The cell, which is composed of fine dry grass, is globular in form, with an opening at top, capable of admitting the finger ; and the whole is so firmly compacted, that it might, without injury, be rolled over the floor."* In case of need the wasp is abundantly furnished by nature with instruments for excavating a burrow out of the solid ground, as she no doubt most commonly docs, — digging the earth with her strong mandibles, and car- rying it off or pushing it out as she proceeds. The entrance-gallery is about an inch or less in diameter, and usually runs in a winding or zigzag direction, from one to two feet in depth. In the chamber to which this gallery leads, and which, when completed, is from one to two feet in diameter, the mother wasp lays the foun- dations of her city, beginning with the walls. The building materials employed by wasps were long a matter of conjecture to scientific inquirers ; for the bluish-grey papery substance of the whole structure has no resemblance to any sort of wax employed by bees for a similar purpose. Now that the discovery has been made, we can with difficulty bring ourselves to believe that a naturalist so acute and indefatigable as M. Reau- mur, should have, for twenty years, as he tells us, endea- voured, without success, to find out the secret. At length, however, his perseverance was rewarded. He remarked a female wasp alight on the sash of his window, and begin to knaw the wood with her mandibles ; and it struck him at once that she was procuring materials for building. He saw her detach from the wood a bundle of fibres about a tenth of an inch in length, and finer than a hair ; and as she did not swallow these, but gathered them into a mass with her feet, he could not doubt that his first idea was correct. In a short time she shifted to another part of the window-frame, carrying with her the fibres she had collected, and to which she * American Ornithology, by Charles Lucien Bonaparte, vol. i. p. 69. T4 INSECT ARCHITECTURE. continued to add, when he caught her, in order to examine the nature of her bundle ; and he found that it Mas not yet moistened nor rolled into a ball, as is always done before employing it in building. In every other respect it had precisely the same colour and fibrous texture as the walls of a vespiary. It struck him as re- markable that it bore no resemblance to wood gnawed by other insects, such as the goat-moth caterpillar, which is granular like sawdust. This would not have suited the design of the wasp, who was well aware that fibres of some length form a stronger texture. He even dis- covered, that before detaching the fibres, she bruised them (les charpissoit^ into a sort of lint (charpie) with her mandibles. All this the careful naturalist imitated by bruising and paring the same wood of the window- sash with his penknife, till he succeeded in making a little bundle of fibres scarcely to be distinguished from that collected by the wasp. We have ourselves frequently seen wasps employed in procuring their materials in this manner, and have always observed that they shift from one part to another more than once in preparing a single load, — a circumstance which we ascribe entirely to the restless temper peculiar to the whole order of hymenopterous insects. Reaumur found that the wood which they preferred was such as had been long exposed to the weather, and is old and dry. White of Selborne, and Kirby and Spence, on the contrary, maintain that wasps obtain their paper from sound timber, hornets only from that which is decayed.* Our own observations, however, confirm the statement of Reaumur with respect to wasps, as, in every instance which has fallen under our notice, the wood selected was very much weathered ; and in one case an old oak post in a garden at Lee, in Kent, half destroyed by dry-rot, was seemingly the resort of all the wasps in the vicinity. In another case, the deal bond in a brick wall, which had been built thirty years, is at this moment (June, * Reaumur, vol. vi. boKom of page 182 ; Hist, of Selb. ii. 228; and Introd. to Entomol. i. 504, 5th edition. SOCIAL-WASPS. 75 1829) literally striped with the gnawings of wasps, which we have watched at the work for hours together. (J. R.) The bundles of ligneous fibres thus detached, are moistened before being used, with a glutinous liquid, which causes them to adhere together, and are then kneaded into a sort of paste, or papier mache. Having prepared some of this material, the mother wasp begins first to line with it the roof of her chamber, for wasps always build downwards. The round ball of fibres which she has previously kneaded up with glue, she now forms into a leaf, walking backwards, and spreading it out with her mandibles, her tongue, and her feet, till it is as thin almost as tissue paper. One sheet, however, of such paper as this would form but a fragile ceiling, quite insufficient to prevent the earth from falling down into the nest. The wasp, ac- cordingly, is not satisfied with her work till she has spread fifteen or sixteen layers one above the other, rendering the wall altogether nearly two inches thick. The several layers are not placed in contact like the layers of a piece of pasteboard, but with small intervals or open spaces between, appearing somewhat like a grotto built with bivalve shells, particularly when looked at on the out- side. This is probably caused by the insect working in a curvilineal manner. Having finished the ceiling, she next begins to build the first terrace of her city, which, under its protection, she suspends horizontally, and not, like the combs in a bee-hive, in a perpendicular position. The suspension of which we speak is also light and elegant, compared with the more heavy union of the hive-bees' combs. It is in fact a hanging floor, immoveably secured by rods of similar materials with the roof, but rather stronger. From twelve to thirty of these rods, about an inch or less in length, and a quarter of an inch in diameter, are constructed for the suspension of the terrace. They are elegant in form, being made gradually narrower towards the middle, and widening at each end, in order, no doubt, to render their hold the stronger. _ 76 IXSECT AUCHITECTUEE. Section of the Social- Wasp's Nest. a a, the external wall ; h, c c, five small terraces of cells for the neuter wasps ; dd, ee, three rows of larger cells for the males and females. The terrace itself is circular, and composed of an im- mense number of cells, formed of the paper already de- scribed, and of almost the same size and form as those of a honeycomb, each being a perfect hexagon, mathema- tically exact, and every hair's breadth of the space com- pletely filled. These cells, however, are not used as honey-pots by wasps, as they are by bees ; for wasps, certain foreign species excepted, make no honey, and the cells are wholly appropriated to the rearing of their young. Like other hymenopterous insects, the grubs are placed with their heads downwards ; and the open- ings of the cells are also downwards ; while their united SOCIAL-WASPS. 77 bottoms form a nearly uniform level upon which the inhabitants of the nest may walk. We have seen, in describing the economy of the carder-bee, that when a young bee had escaped from its cradle-cell, and so ren- dered it empty, that cell was subsequently appropriated to the storing of honey. But in the case of wasps, a cell thus evacuated is immediately cleaned out and repaired for the reception of another grub — an egg being laid in it by a female wasp as soon as it is ready. When the foundress wasp has completed a certain number of cells, and deposited eggs in them, she soon intermits her building operations, in order to procure food for the young grubs, which now require all her care. In a few weeks these become perfect wasps, and lend their assistance in the extension of the edifice ; en- larging the original coping of the foundress by side walls, and forming another platform of cells, suspended to the first by columns, as that had been suspended to the ceilinc. A represents one of tlie rods from wliicli the terraces are suspended. B, a portion of the external crust. In this manner several platforms of combs are con- structed, the outer walls being extended at the same time ; and, by the end of the summer, there is generally from twelve to fifteen platforms of cells. Each contains about 1060 cells — forty-nine being contained in an inch and a half square, and, of course, making the enormous number of about 16,000 cells in one colony. Reaumur, upon these data, calculates that one vespiary may produce every year more than 30,000 wasps, reckoning only 78 IXSECT ARCHITECTURE. 10,000 cells, and each serving successively for the cradle of three generations. But, although the whole structure is built at the expense of so much labour and ingenuity, it has scarcely been finished ^before the winter sets in, when it becomes nearly useless, and serves only for the abode of a few benumbed females, who abandon it on the approach of spring, and never return ; for wasps do not, like mason-bees, ever make use of the same nest for more than one season. Both Reaumur and the younger Huber studied the proceedings of the common wasp in the manner which has been so successful in observing bees — by means of glazed hives, and other contrivances. In this, these na- turalists were greatly aided by the extreme affection of wasps for their young ; for though their nest is carried off, or even cut in various directions, and exposed to the light, they never desert it, nor relax their attention to their progeny. When a wasp's nest is removed from its natural situation, and covered with a glass hive, the first operation of the inhabitants is to repair the injuries it has suffered. They carry off with surprising activity all the earth or other matters which have fallen by accident into the nest ; and when they have got it thoroughly cleared of everything extraneous, they begin to secure it from further derangement, by fixing it to the glass with papyraceous columns, similar to those which we have al- ready described. The breaches which the nest may have suffered are then repaired, and the thickness of the walls is augmented, with the design, perhaps, of more effectually excluding the light. The nest of the hornet is nearly the same in structure with that of the wasp ; but the materials are considerably coarser, and the columns to which the platforms of cells are suspended are larger and stronger, the middle one being twice as thick as any of the others. The hornet, also, does not build underground, but in the cavities of trees, or in the thatch or under the eaves of barns. Reaumur once found upon a wall a hornet's nest which had not been long begun, and had it transferred to the SOCIAL-WASPS. 79 outside of his study-window ; but in consequence, as he imagined, of the absence of the foundress hornet at the time it was removed, he could not get the other five liornets, of which the colony consisted, either to add to the building or repair the damages which it had sustained. Hornet's Nest in its first sta^e. M. Reaumur differs from our English naturalists, White, and Kirby and Spence, with respect to the ma- terials employed by the hornet for building. The latter say that it employs decayed wood ; the former, that it uses the bark of the ash-tree, but takes less pains to split it into fine fibres than wasps do ; not, however, because it is destitute of skill ; for in constructing the suspensory columns of the platforms, a paste is prepared little infe- rior to that made by wasps. We cannot, from our own observations, decide which of the above statements is cor- 80 INSECT ARCHITECTUEE. rect, as we have only once seen a hornet procuring mate- rials, at Compton-Bassett, in Wiltshire ; and in that case it gnawed the inner bark of an elm which had been felled for several months, and was, consequently, dry and tough. Such materials as this would account for the common yellowish-brown colour of a hornet's nest. (J. R.) When hornets make choice of a tree for their domicile, they select one which is in a state of decay, and already partly hollowed ; but they possess the means, in their sharp and strong mandibles, of extending the excavation to suit their purposes ; and Reaumur frequently witnessed their operations in mining into a decayed tree, and car- rying off M'hat they had gnawed. He observed, also, that in such cases they did not make use of the large hole of the tree for an enti'ance, but went to the trouble of digging a gallery, sufficient for the passage of the largest hornet in the nest, through the living and unde- cayed portion of the tree. As this is perforated in a winding direction, it is no doubt intended for the pur- pose of protecting the nest from the intrusion of depre- dators, who could more easily efiect an entrance if there were not such a tortuous way to pass through. One of the most remarkable of our native social- wasps is the tree-wasp {Vespa Bj'itannicd), which is not un- common in the northern, but is seldom to be met with in the southern parts of the island. Instead of burrow- ing in the ground like the common wasp ( Vespa vul- garis,^ or in the hollows of trees like the hornet ( Vespa crahro), it boldly swings its nost from the extremity of a branch, where it exhibits some resemblance, in size and colour, to a Welsh wig hung out to dry. We have seen more than one of these nests on the same tree, at Catrine, in Ayrshire, and at Werayss Ray, in Renfrew- shire. The tree which the Britannic wasp prefers is the silver fir, whose broad fiat branch serves as a protection to the suspended nest both from the sun and the rain. We have also known a wasp's nest of this kind in a gooseberry-bush, at Red-house Castle, East Lothian. The materials and structure are nearly the same as those SOCIAL-WASPS. 81 employed by the common wasp, and which we have al- ready described. (J. R.) A singular nest of a species of wasp is figured by Reaumur, but is apparently rare in this country, as Kirby and Spence mention only a single nest of similar con- struction, found in a garden at East-Dale. This nest is of a flattened globular figure, and composed of a groat number of envelopes, so as to assume a considerable re- semblance to a half-expanded Provence rose. The British specimen mentioned by Kirby and Spence had only one platform of cells ; Reaumur's had two ; but there was a large vacant space, which would probably have been filled with cells, had the nest not been taken away as a specimen. The whole nest was not much larger than a rose, and was composed of paper exactly similar to that employed by the common ground-wasp.* * Two British species of wasp, Vespa Hohaiica, Fabr., and f'espa Bi-itajinica, Leach, if indeed they be truly distinct spe- cies, make pendent vespiaries, attached to the braiicli of a shiub or tree. The nest of the Fespa Holsatica is said to be much larger than that of the other, and in the north of Eng- land it is often found in gooseberry-bushes. A nest of this kind we have ourselves seen in such a bush, in Derbyshire, — it v/as pendent and loosely constructed externally of foliaceous layers. In the Mag. of Nat. Hist. 1839, p. 458, Mr. Shuck- ard gives an account cf the nest of a wasp, which he regards as Fespa Britavjiica, — remarkable for the material of which it was ci.-nstiucted, and for the locality in which it was found. This nest, which was exhibited at a meeting of the Entomo- logical Society, was found near Croydon, built in a sparrov/'s nest, and attached to the lining feathers. '"The smallness of the nest," says Mr. Shuckard, "and also of the tier of cells, as well as the peculiar material of which it appeared com] osed, led to a discussion, the tendency of which seemed to support the opinion that it was most proLably the nest of a Po/istes, a social-wasp not yet found in this counlry, but if not of Po- listes, certainly not yet determined or known." Tlie nest was ovate, about an inch and a half long, with a tier of cells in- ternally, originating from a common pedicle. It appeared to be constructed " of the agglutinated particles of a soft white VOL. I. E INSECT ARCHITECTURE. Wasp's Nest. There is another species of social- wasp (^Epipone nidu- lans, Latr.) meriting attention from the singular con- struction of its nest. It forms one or more terraces of cells, similar to those of the common wasp, but without the protection of an outer \^all, and quite exposed to the weather. Swammerdam found a nest of this description attached to the stem of a nettle. Reaumur says they are sometimes attached to the branch of a thorn or other wood, probably willow, very imperfectly triturated;" whence it had externally a rough granulated appearance. It was sprinkled with black specks, arising perhaps from the inter- mixture of more decayed portions of the wood ; and was of a very fragile texture. " The nature of the material, and its un- finished execution, as well as the situation in which it was found, appear to me to be its own peculiarities, and I must necessarily consider it merely an accidental variation in ma- terial and locality from the usual nests of the Vespa Britan- nica of Leach." — Mr. Shuckard concludes his paper by stating that he strongly suspects the identity of Fespa Holsatica and Fespa Britannica, SOCIAL-WASPS. 83 shrub, or to stalks of grass ; — peculiarities which prove that there are several species of these wasps. The most remarkable circumstance in the architecture of this species of vespiary is, that it is not horizontal, like those formerly described, but nearly vertical. The rea- son appears to be, that if it had been horizontal, the cells must have been frequently filled with rain ; whereas, in the position in which it is placed, the rain runs off with- out lodging-. It is, besides, invariably placed so as to face the north or the east, and consequently is less ex- "Wasp's Cells attached to a Brancli. posed to rains, which most frequently come with south- erly or westerly winds. It is another remarkable pecu- liarity, that, unlike the nests of other wasps, it is covered with a shining coat of varnish, to prevent moisture from soaking into the texture of the wasp's paper. The laying on this varnish, indeed, forms a considerable portion of E 2 84 IXSECT ARCHITECTUKE. Ihe labour of the colony, and individuals may be seen employed for houi*s together spreading it on with their tongues. Few circumstances are more striking, with regard to insects, as Kirby and Spencc justly remark, than the great and incessant labour which maternal aftection for their progeny leads them to undergo. Some of these exertions are so disproportionate to the size of the insect, that nothing short of ocular conviction could attribute them to such an agent. A wild bee, or a wasp, for in- stance, as we have seen, will dig a hole in a hard bank of earth some inches deep, and five or six times its own size, labouring unremittingly at this arduous task for several days in succession, and scarcely allowing itself a moment for eating or repose. It will then occupy as much time in searching for a store of food ; and no sooner is this finished, than it will set about repeating the process, and, before it dies, will have completed five or six similar cells, or even more. We shall have occasion more particularly to dwell upon the geometrical arrangement of the cells, both of the wasp and of the social-bee, in our description of those interesting operations, which have long attracted the notice, and commanded the admiration, of mathematicians and naturalists. A few observations may here be pro- perly bestowed upon the mateiial with which the wasp- family construct the interior of their nests. The wasp is a paper-maker, and a most perfect and intelligent one. While mankind were arriving, by slow degrees, at the art of fabricating this valuable substance, the wasp was making it before their eyes, by yerj much the same process as that by which human hands now manufacture it with the best aid of chemistry and ma- chinery. While some nations carved their records on wood, and stone, and brass, and leaden tablets, — others, more advanced, wrote with a style on wax, — others em- ployed the inner bark of trees, and others the skins of animals rudely prepared, — the wasp was manufacturing a firm and durable paper. Even when the papyrus was rendered more fit, by a process of art, for the trans- SOCIAL- WASPS. 85 mission of ideas in writing, the wasp was a better artisan than the Egyptians ; for the early attempts at paper- making were so rude, that the substance produced was ahnost useless, from being extremely friable. The ]}aper of the papyrus was formed of the leaves of the plant, dried, pressed, and polished ; the wasp alone knew how to reduce vegetable fibres to a pulp, and then unite them by a size or glue, spreading the substance out into a smooth and delicate leaf. This is exactly the process of ])aper-making. It would seem that the wasp knows, as the modern paper-makers now know, that the fibres of rags, whether linen or cotton, are not the only materials that can be used in the formation of paper; she employs other vegetable matters, converting them into a proper consistency by her assiduous exertions. In some re- spects she is more skilful even than our paper-makers, for she takes care to retain her fibres of sufficient length, by which she renders nm' paper as strong as she requires. Many manufacturers of the present day cut their mate- rial into small bits, and thus produce a rotten article. One great distinction between good and bad paper is its toughness ; and this difference is invariably produced by the fibre of which it is composed being long, and there- fore tough ; or short, and therefore friable. The wasp has been labouring at her manufacture of paper, from her first creation, with precisely the same instruments and the same materials ; and her success has been unvarying. Her machinery is very simple, and there- fore it is never out of order. She learns nothing, and she forgets nothing. Men, from time to time, lose their excellence in particular arts, and they are slov.' in finding out real improvements. Such improvements are often the efrect of accident. Paper is now manufactured ver}^ extensively by machinery, in all its stages ; and thus, instead of a single sheet being made by hand, a stream of paper is poured out, which would form a roll large enough to extend round the globe, if such a length were desirable. The inventors of this machinery, Messrs. Fourdrinier, it is said, spent the enormous sum of 40,000/. in vain attempts to render the machine capable 86 IKSECT ARCHITECTURE. of determining with precision the width of the roll ; and, at last, accomplished their object, at the suggestion of a bystander, by a strap revolving upon an axis, at a cost of three shillings and sixpence. Such is the difference be- tween the workings of human knowledge and expe- rience, and those of animal instinct. We proceed slowly and in the dark — but our course is not bounded by a narrow line, for it seems difficult to say what is the per- fection of any art ; animals go clearly to a given point — but they can go no further. We may, however, learn something from their perfect knowledge of what is within their range. It is not improbable that if man had attended in an earlier state of society to the labours of wasps, he w^ould have sooner known how to make paper. We are still behind in our arts and sciences, because we have not always been observers. If we had watched the operations of insects, and the structure of insects in general, with more care, we might have been far advanced in the knowledge of many arts which are yet in their infancy, for nature has given us abundance of patterns. We have learnt to perfect some instruments of sound by examining the structure of the human ear ; and the mechanism of an eye has suggested some valuable improvements in achromatic glasses. Reaumur has given a very interesting account of the wasps of Cayenne {Chartergus nidulans), which hang their nests in trees.* Like the bird of Africa called the social grosbeak {Loxia socio), they fabricate a perfect house, capable of containing many hundreds of their community, and suspend it on high out of the reach of attack. But the Cayenne wasp is a more expert artist than the bird. He is a pasteboard-maker ;— and the card with which he forms the exterior covering of his abode is so smooth, so strong, so uniform in its texture, and so white, that the most skilful manufacturer of this substance might be proud of the work. It takes ink ad- mirably. * Memoires sur les Insectes, torn, vi., mem. vii. See also Bonnet, vol. ix. SOCIAL-WASPS. 87 The nest of the pasteboard-making wasp is impervious to water. It hangs upon the branch of a tree, as repre- sented in the engraving ; and those rain-drops which penetrate through the leaves never rest upon its hard and polished surface. A small opening for the entrance of the insects terminates its funnel-shaped bottom. It is impossible to unite more perfectly the qualities of light- ness and strength. In the specimen from which we take our descrip- Nest of the Pasteboard maker Wasp, with part removed to show the arrangement of the Cells. 88 INSECT ARCHITECTURE. tion, the length of which is nine inches, six stoat cir- cular platforms stretch internally across, like so many fioors, and fixed all round to the walls of the nest. They are smooth above, with hexagonal cells on the under surface. These platforms are not quite flat, but ratlier concave above, like a watch-glass reversed ; the centre of each platform is perforated for the admission of the wasps, at the extremity of a short funnel-like pro- joction, and through this access is gained from story to story. On each platform therefore can the wasps walk leisurely about, attending to the pupae secured in the cells, which, with the mouths downward, cover the ceiling above their heads — the height of the latter being just convenient for their work. Pendent wasps'-nests of enormous size are found in Ceylon, suspended often in the talipot-tree at the height of seventy feet. The appearance of these nests thus elevated, with the larger leaves of the tree, used by the natives as umbrellas and tents, v/aving over them, is very singular. Though no species of European wasp is a storer of honey, yet this rule does not apjily to certain species of South America. In the ' Annals and Maga- zine of Natural History' for June, 1841, will be found a detailed account, with a figure, of the pendent nest of a species termed by Mr. A. White Myraptera scutellaris. The external case consists of stout cardboard covered with conical knobs of various sizes. The entrances are artfully protected by pent-roofs from the weather and heavy rains ; and are tortuous, so as to render the ingress f»f a moth or other large insect difficult. Internally are fourteen combs, exclusive of a globular mass, the nucleus ol several circular combs, which are succeeded by others of an arched form — that is, constituting segments of ciicles. ]\Iany of the uppermost combs were found to have the cells filled with honey of a brownish red colour, but which had lost its flavour. After entering into some m'.nute details, Mr. A. White makes the following inte- resting observations : — " Azara, in the account of his residence in various parts of South America, mentions the fact of several wasps of these countries collecting SOCIAL-WASPS. 89 honey. The Baron Wachenaer, who edited the French translation of this work published in 1809, thought that the Spanish traveller, who was unskilled in entomology, had made some mistake with regard to the insects, and regarded the so-called ivasps as belonging to some bee of the genus of which Apis amalthea is the type {Meli- 2^ond). Latreille (who afterwards corrected his mistake) also believed that they must be referred to the genera Melipona or Trigona — insects which in South America take the place of our honey-bee. These authoi-s were after- wards clearly convinced of the correctness of Azara's observations, by the circumstance of M. Auguste de St. Hilaire finding near the river Uruguay an oval grey- coloured nest of a papery consistence, like that of the European wasps, suspended from the branches of a small shrub about a foot from the ground ; he and two other attendants partook of some honey (contained in its cells) and found it of an agreeable sweetness, free from the phar- maceutic taste which so frequently accompanies European hcney. He gives a detailed account of its poisonous effects on himself and his two men." Afterwards he procured specimens of the wasp, which was described by Latreille under the name of Polistes Lecheguana. It v.'ould seem that the nest described by Mr. White agrees with that of a wasp termed CInguana by Azara (or Lecheguana), and is very different to the slight papery nest of the Polistes Lecheguana of Latreille. We may add that M. Auguste de St. Hilaire speaks of two species of wasp remarkable for storing honey in South America ; the honey of one is white, of the other reddish. That the habits of these honey-wasps m-ust differ considerably from those of any of our European species we may at once admit ; perhaps in some points of their econcmy these insects may approach the bee. s 3 IXSKCT ARCHITECTURE. CHAPTER V. Architecture of the Bee-liive. Part of a Honeycomb, and Bees at work. Although the hive-bee (Apis mellificd) has engaged the attention of the curious from the earliest ages, recent discoveries prove that we are yet only beginning to arrive at a correct knowledge of its wonderful proceedings. Pliny informs us that Aristomachus, of Soles, in Cilicia, devoted fifty-eight years to the study ; and that Philis- cus the Thracian spent his whole life in forests for the purpose of observing them. But in consequence (as we may naturally infer) of the imperfect methods of research, HIVE-BEES. 91. assuming that what they did discover was known to Aristotle, Cokimella, and Pliny, we are justified in pro- nouncing- the statements of these philosophers, as well as the embellished poetical pictures of Virgil, to be nothing more than conjecture, almost in every particular erro- neous. It was not indeed till 1712, when glass hives were invented by Maraldi, a mathematician of Nice, that what we may call the in-door proceedings of bees could be observed. This important invention was soon afterwards taken advantage of by JNI. Reaumur, who laid the foundation of the more recent discoveries of John Hunter, Schirach, and the Rubers. The admir- able architecture which bees exhibit in their miniature cities has, by these and other naturalists, been investi- gated with great care and accuracy. We shall endea- vour to give as full an account of the wonderful struc- tures as our limits will allow. In this we shall chiefly follow M. Iluber, the elder, whose researches appear almost miraculous when we consider that he was blind. At the early age of seventeen this remarkable man lost his sight by gtitta serena, the " drop serene " of our own Milton. But though cut off from the sight of Nature's works, he dedicated himself to their study. He saw them through the eyes of the admirable woman whom he married ; his philosophical reasonings pointed out to her all that he wanted to ascertain ; and as she reported to him from time to time the results of his ingenious experiments, he was enabled to complete, by diligent investigation, one of the most accurate and satisfactory accounts of the habits of bees which have ever been produced. It had long been known that the bees of a hive con- sist of three sorts, which were ascertained by M. Reaumur to be distinguished as workers or neuters, con- stituting the bulk of the population ; drones or males, the least numerous class ; and a single female, the queen and mother of the colony. Schirach subsequently discovered the very extraordinary fact, which Huber and others have proved beyond doubt, that when a hive is acci- dentally deprived of a queen, the grub of a worker can be and is fed in a particular manner so as to become a 92 IXSECT ARCHITECTURE. queen and supply the loss.* But another discovery of M. Huber is of more importance to the subject of arclii- tecture now before us. By minute research he ascer- tained that the workers which had been considered by former naturalists to be all alike, are divided into two important classes, nurse-bees and wax-makers. The nurse-bees are rather smaller than the wax- workers, and even when gorged with honey their belly does not, as in the others, appear distended. Their business is to collect honey, and impart it to their com- panions ; to feed and take care of the young grubs, and to complete the combs and cells which have been founded by the others ; but they are not charged with provision- ing the hive. The icax-worhers, on the other hand, are not only ai little larger, but their stomach, when gorged with honey, is capable of considerable distention, as M. Huber proved by repeated experiments. He also ascertained that neither of the species can alone fulfil all the func- tions shared among the workers of a hive. He painted those of each class with different colours, in order to study their proceedings, and their labours were not inter- changed. In another experiment, after supplying a hive deprived of a queen with brood and pollen, he saw the nurse-bees quickly occupied in the nutrition of the grubs, while those of the wax-working class neglected them. When hives are full of combs, the wax-workers disgorge their honey into the ordinary magazines, making no wax: but if they v»'ant a reservoir for its reception, and if their queen does not find cells ready made wherein to lay her eggs, they retain the honey in the stomach, and in twenty -four hours tliey produce wax. Then the la- boar of constructing combs begins. It might perhaps be supposed that, when the country * It is light to remark that Hiiish and others have suggested that tlie grubs thus rjyalized may originally be misplaced queens; yet tins admission is not necessary, since ]\Iadlle. Ju- rine has proved, by dissection, the workers to be imperfect females. HIVE-BEES. 93 does not afford honey, the wax-workers consume the provision stored up in the hive. But they are not per- mitted to touch it. A portion of honey is carefully pre- served, and the cells containing it are protected by a waxen covering, which is never removed except in case of extreme necessity, and when honey is not to be other- wise procured. The cells are at no time opened during summer ; other reservoirs, always exposed, contribute to the daily use of the community ; each bee, however, supplying itself from them with nothing but what is re- quired for present wants. Wax-workers appear with large bellies at the entrance of their hive, only when the country affords a copious collection of honey. From this it may be concluded, that the production of the waxy matter depends on a concurrence of circumstances not invariably subsisting. Nurse-bees also produce wax, but in a very inferior c^uantity to what is elaborated by the real wax-workers. Another characteristic whereby an attentive observer can determine the moment of bees collecting sufficient honey to produce wax, is the strong odour of both these substances from the hive, which is not equally intense at any other time. From such data, it v.as easy for M. Huber to discover whether the bees worked in wax in his own hives, and in those of the other cultivators of the district. There is still another sort of bees, first observed by Huber in 1809, which appear to be only casual inmates of the hive, and which are driven forth to starve, or are killed in conflict. They closely resemble the ordinary workers, but are less hairy, and of a much darker colour. These have been called black bees, and are supposed by Huber to be defective bees;* but Kirby and Spence conjecture that they are toil-worn superannuated workers, of no further use, and are therefore sacrificed, because burdensome to a community which tolerates no unne- cessary inmates. The very great numbers of black bees, however, which sometimes appear, does not well accord with such an opinion. The subject remains, therefore, still in uncertainty. * Kuber on Bees, p. 338. 84 INSECT ARCHITECTURE. Preparatiox or Wax. In order to build the beautiful combs, which every one must have repeatedly seen and admired, it is indispens- able that the architect-bees should be provided with the materials — with the wax, in short, of which they are principally formed. Before we follow them, therefore, to the operation of building, it may be necessary to in- quire how the wax itself is procured. Here the disco- veries of recent inquirers have been little less singular and unexpected than in other departments of the history of these extraordinary insects. Now that it has been proved that wax is secreted by bees, it is not a little amusing to read the accounts given by our elder natural- ists, of its being collected from flowers. Our country- man, Thorley,* appears to have been the first who sus- pected the true origin of wax, and Wildman (1769) seems also to have been aware of it ; but Reaumur, and particularly Bonnet, though both of them in general shrewd and accurate observers, M'cre partially deceived by appearances. The bees, we are erroneously told, search for wax ''upon all sorts of trees and plants, but especially the rocket, the single poppy, and in general all kinds of flowers. They amass it with their hair, with which their whole body is invested. It is something pleasant to see them roll in the yellow dust which falls from the chives to the bottom of the flowers, and then return covered with the same grains ; but their best method of gathering the wax, especially when it is not very plen- tiful, is to carry away all the little particles of it with their jaws and fore feet, to press the wax upon them into little pellets, and slide them one at a time, with their middle feet, into a socket or cavity, that opens at their hinder feet, and serves to keep the burthen fixed and steady till they return home. They are sometimes ex- * Melisselogia, or Female Monarchy, 8vo., Lend. 1744. HIVE-BEES. 95 posed to inconveniences in this work hy the motion of the air, and the delicate texture of the flowers which bend under their feet, and hinder them from packing up their booty, on which occasions they fix themselves in some steady place, where they press the wax into a mass, and wind it round their legs, making frequent returns to the flowers ; and when they have stocked themselves with a sufficient quantity, they immediately repair to their habitation. Two men, in the compass of a whole day, could not amass so much as two little balls of wax ; and yet they are no more than the common burthen of a single bee, and the produce of one journey. Those who are employed in collecting the wax from flowers are assisted by their companions, who attend them at the door of the hive, ease them of their load at their arrival, brush their feet, and shake out the two balls of wax ; upon which the others return to the fields to gather new treasure, while those who disburthencd them convey their charge to the magazine. But some bees, again, when they have brought their load home, cany it them- selves to the lodge, and there deliver it, laying hold of one end by their hinder feet, and with their middle feet sliding it out of the cavity that contained it ; but this is evidently a work of supererogation which they are not obliged to perform. The packets of wax continue a few moments in the lodge, till a set of officers come, who are charged with a third commission, which is to knead this wax with their feet, and spread it out into different sheets, laid one above another. This is the unwrought wax, which is easily distinguished to be the produce of different flowers, by the variety of colours that appear on each sheet. When they afterwards come to work, they knead it over again, they purify and whiten, and then reduce it to a uniform colour. They use this wax with a wonderful frugality ; for it is easy to observe that the whole family is conducted by prudence, and all their actions regulated by good government. Everything is granted to necessity, but nothing to superfluity ; not the least grain of wax is neglected, and if they waste it, they SJO IXSECT ARCHITECTL'KE. are frequently obliged to provide more ; at those very times when they want to get their provision of honey, they take off the wax that closed the cells, and carry it to the magazine."* Reaumur hesitated in believing that this was a correct view of the subiect, from observing^ the g^reat difference between wax and pollen ; but he was inclined to think the pollen might be swallowed, partially digested, and disgorged in the form of a kind of paste. Schirach also mentions, that it was remarked by a certain Lusatian, that wax comes from the rings of the body, because, on Avithdrawing a bee while it is at work, and extending its body, the wax may be seen there in the form of scales. The celebrated John Hunter shrewdly remarked that the pellets of pollen seen on the thighs of bees are of different colours on different bees, while the shade of the new-made comb is always uniform ; and therefore he concluded that pollen was not the origin of wax. Pollen also, he observed, is collected with greater avidity for old hivQg, where the comb is complete, than for those where it is only begun, which would hardly be the case were it the material of wax. He found that when the weather was cold and wet in June, so that a young swarm was prevented from going abroad, as much comb was constructed as had been made in an equal time when the weather was favourable and fine. The pellets of pollen on the thighs being thence proved not to be wax, he came to the conclusion that it was an external secretion, originating between the plates of the belly. When he first observed this, he felt not a little embarrassed to explain the phenomenon, and doubted whether new plates were forming, or whether bees cast their old ones as lobsters do their shell. By melting the scales, he ascertained at least that they were wax ; and his opinion was confirmed by the fact, that the scales are only to be found during the season when the combs ai*e constructed. But he did not succeed in com- * De la Plucbe, Spectacle de la Nature, vol. i. HIVE-BEES. 97 pleting the discovery by observing the bees actually de- tach the scales, though he conjectured they might be taken up by others, if they were once shaken out from between the rings.* We need not be so much surprised at mistakes com- mitted upon this subject, when we recollect that honey itself was believed by the ancients to be an emanation of the air — a dew that descended upon flowers, as if it had a limited commission to fall only on them. The ex- posure and correction of error is one of the first steps to genuine knowledge ; and when we are aware of the stumbling-blocks which have interrupted the progress of ethers, we can always travel more securely in the way of truth. That wax is secreted is proved both by the wax-pouches Avithin the rings of the abdomen, and by actual experi- ment. Iluber and others fed bees entirely upon honey or sugar, and, notwithstanding, wax A\as produced and combs formed as if they had been at liberty to select their Ibod. " When bees were confined," says M. Huber, " for the purpose of discovering Nvhether honey was suf- ficient lor the production of wax, they supported their capti\ity patiently, and showed uncommon perseverance in rebuilding their combs as we removed them. Our ex- periments required the presence of grubs ; honey and v»ater had to be provided ; the bees were to be su})plied with combs containing brood, and at the same time it was necessary to confine them, that they might not seek pollen abroad. Having a swarm by chance, which had become useless iiom sterility of the queen, we devoted it for our investigation in one of my leaf-hives, which was glazed on both sides. We removed the queen, and substituted combs containing eggs and young grubs, but no cell with iarina ; even the smallest particle of the substance which John Hunter conjectured to be the basis of the nutriment of the young was taken away. "Nothing remai'kable occurred during the first and second day : the bees brooded over the young, and seemed * Philosoi^hlcal Trans, for 1792, p. 143. 98 LNSECT ARCHITECTURE. to take an interest in them ; but at sunset, on the third, a loud noise was heard in the hive. Impatient to discover the reason, v,e opened a shutter, and saw all in confusion ; the brood was abandoned, the workers ran in disorder over the combs, thousands rushed towards the lower part of the hive, and those about the entrance gnawed at its grating. Their design was not equivocal ; they wished to quit their prison. Some imperious necessity evidently obliged them to seek elsewhere what they could not find in the hive; and apprehensive that they might perish if I restrained them longer from yielding to their instinct, I set them at liberty. The whole swarm escaped ; but the hour being unfavourable for their collections, they flew around the hive, and did not depart far from it. In- creasing darkness and the coolness of the air compelled them very soon to return. Probably these circumstances calmed their agitation ; for we observed them peaceably remounting their combs ; order seemed re-established, and we took advantage of this moment to close the hive. " Next day, the 19th of July, we saw the rudiments of two royal cells, which the bees had formed on one of the brood-combs. This evening, at the same hour as on the precedinof, we again heard a loud buzzing in the closed hive ; agitation and disorder rose to the highest degree, and we were again obliged to let the swarm escape. The bees did not remain long absent from their habitation ; they quieted and returned as before. We remarked on the 20th that the royal cells had not been continued, as would have been the case in the ordinary state of things. A great tumult took place in the evening ; the bees ap- peared to be in a delirium ; we set them at liberty, and order was restored on their return. Their captivity having endured five days, we thought it needless to protract it farther ; besides, we were desirous of knowing whether the brood was in a suitable condition, and if it had made the usual progress ; and we wished also to try to discover what might be the cause of the periodical agitation of the bees. M. Burnens (the assistant of Huber), having ex- posed the two brood-combs, the royal cells were imme- diately recognised ; but it was obvious that they had not HIVE-BEES. 99 been enlarged. Wliy should they ? Neither eggs, grubs, nor that kind of paste peculiar to the individuals of their species were there ! The other cells were vacant likewise ; no brood, not an atom of paste, was in them. Thus, the worms had died of hunger. Had we precluded the bees from all means of sustenance by removing the farina ? To decide this point, it was necessary to confide other brood to the care of the same insects, now giving them abundance of pollen. They had not been enabled to make any collections while we examined their combs. On this occasion they escaped in an apartment where the windows were shut ; and after substituting young worms for those they had allowed to perish, we returned them to their prison. Next day we remarked that they had resumed courage ; they had consolidated the combs, and remained on the brood. They were then provided with fragments of combs, where other workers had stored up farina ; and to be able to observe what they did with it, we took this substance from some of their cells, and spread it on the board of the hive. The bees soon dis- covered both the farina in the combs and what we had exposed to them. They crowded to the cells, and also descending to the bottom of the hives, took the pollen grain by grain in their teeth, and conveyed it to their mouths. Those that had eaten it most greedily, mounted the combs before the rest, and stopping on the cells of the young worms, inserted their heads, and remained there for a certain time. iSI. Bm'nens opened one of the divisions of the hive gently, and powdered the workers, for the purpose of recognising them when they should ascend the combs. He observed them during several hours, and by this means ascertained that they took so great a quantity of pollen only to impart it to their young. Then withdrawing the portions of comb which had been placed by us on the board of the hive, we saw that the pollen had been sensibly diminished in quantity. They were returned to the bees, to augment their provision still further, for the purpose of extending the experiment. The royal, as well as several common, cells were soon closed ; and, on opening the hive, all the worms were 100 IKSECT ARCHITECTURE. found to have prospered. Some still had their food be- fore them ; the cells of others that had spun were shut with a waxen covering. *' We witnessed these facts repeatedly, and always with equal interest. They so decisively prove the regard of the bees towards the grubs which they arc intrusted with rearing, that we shall not seek for any other explanation of their conduct. Another fact, no less extraordin.ny, and much more difficult to be accounted .for, was exhi- bited by bees constrained to work in wax, several times successively, from the syrup of sugar. Towards the close of the experiment they ceased to feed the young, though in the beginning these had received the usual attention. They even frequently dragged them from their cells, and carried them out of the hive."* Mr. Wiston, of Germantown, in the United States, mentions a fact conclusive on this subject. " I had,'* sa^'S he, " a late swarm last summer, which, in conse- quence of the drought, filled only one box with honey. As it was late in the season, and the food collected would not enable the bees to subsist for the winter, I shut up the hive, and gave them half a pint of honey every day. Tliey immediately set to work, filled the empty cells, and then constructed new cells enough to fill another box, in which they deposited the remainder of the honey." A more interesting proof is thus related by the same gentleman. ** In the summer of 1824, I traced some wild bees, which had been feeding on the flowers in my meadow, to their home in the woods, and which I found in the body of an oak tree, exactly fifty feet above the ground. Having caused the entrance to the hive to be closed by an expert climber, the limbs were separated in detail, until the trunk alone was left standing. To the upper extremity of this, a tackle-fall was attached so as to connect it with an adjacent tree, and, a saw being ap- plied below, the naked trunk was cut through. Vvlien the immense weight was lowered nearly to the earth, the * Huber on Bees. HIVE-BEES. 101 ropes broke, and the mass fell Avith a violent crash. The part of the tree which contained the hive, separated by the saw, was conveyed to my garden, and placed in a vertical })osition. On being released, the bees issued out by thousands, and though alarmed, soon became recon- ciled to the change of situation. By removing a part of the top of the block the interior of the hive was exposed to view, and the comb itself, nearly six feet in height, was observed to have fallen down two feet below the roof of the cavity. To repair the damage was the first object of the labourers ; in doing which, a large part of their store of honey was expended, because it was at too late a season to obtain materials from abroad. In the following February these industrious, but unfortunate insects, issuing in a confused manner from the hive, fell dead in thou- sands around its entrance, the victims of a poverty created by their efforts to repair the ruins of their habit- ation."* In another experiment, M. Huber confined a swarm so that they had access to nothing beside honey, and five times successively removed the combs with the precaution of preventing the escape of the bees from the apartment. On each occasion they produced new combs, which puts it beyond dispute that honey is sufficient to effect the secretion of wax without the aid of pollen. Instead of supplying the bees with honey, they were subsequently fed, exclusively, on pollen and fruit; but though they were kept in captivity for eight days under a bell-glass, with a comb containing nothing but farina, they neither made wax nor was any secreted under the rings. In another series of ex})eriments, in which bees were fed with different sorts of sugar, it was found that nearly one- sixth of the sugar was converted into wax, dark coloured sugar yielding more than double the quantity of reHned sugar. It may not be out of place to subjoin the few anatomical and physiological facts which have been ascertained by Huber, Madile. Jurine, and Latreille. ♦ American Quarterly Review for June, 1828, p. 3£2. 102 INSECT ARCHITECTURE. The first stomach of the worker-bee, according to Latreille,* is appropriated to the reception of honey, but this is never found in the second stomach, which is sur- rounded with muscular rings, and from one end to the other very much resembles a cask covered with hoops. It is within these rings that the wax is produced, but the secreting vessels for this purpose have hitherto escaped the researches of the acutest naturalists. Huber, how- ever, plausibly enough conjectures that they are contained in the internal lining of the wax-pockets, which consists of a cellular substance reticulated with hexagons. The wax-pockets themselves, which are concealed by the over- lapping of the rings, may be seen by pressing the abdo- men of a worker-bee so as to lengthen it, and separate the rings further from each other. When this has been done, there may be seen on each of the four intermediate hoops of the belly, and separated by what may be called the keel (carina)^ two whitish-coloured pouches, of a soft texture, and in the form of a trapezium. Within, the Worker-bee, magnlQed — showing the position of the scales of Wax. little scales or plates of wax are produced from time to * Latreille, ^em. Acad, des Sciences, 1821 i HIVE-BEES. 103 time, and are removed and employed as we shall presently see. We may remark, that it is chiefly the wax-workers which produce the wax ; for though the nurse-bees are furnished with wax-pockets, they secrete it only in very small quantities ; while in the queen-bee, and the males or drones, no pockets are discoverable. Abdomen of Wax- worker Bee. " All the scales," says Huber, '' are not alike in every bee, for a difference is perceptible in consistence, shape, and thickness ; some are so thin and transparent as to re- quire a magnifier to be recognised, or we have been able to discover nothing but spiculae similar to those of water freezing. Neither the spiculae nor the scales rest imme- diately on the membrane of the pocket, a slight liquid medium is interposed, serving to lubricate the joinings of the rings, or to render the extraction of the scales easier, as otherwise they might adhere too firmly to the sides of the pockets." M. Huber has seen the scales so large as to project beyond the rings, being visible without stretch- ing the segments, and of a whitish yellow, from greater thickness lessening their transparency. These shades of 104 INSECT AHCHITECTURE. difference in the scales of various bees, their enlarged dimensions, the fluid interposed beneath them, the cor- respondence between the scale, and the size and form of the pockets, seem to infer the oozing of this substance through the membranes whereon it is moulded. He was confirmed in this opinion by the escape of a transparent fluid on piercing the membrane, whose internal surface seemed to be applied to the soft parts of the belly. This he found coagulated in cooling, when it resembled wax, and again liquefied on exposure to heat. The scales themselves, also, melted and coagulated like wax.* By chemical analysis, however, it appears that the wax of the rings is a more simple substance than that which composes the cells ; for the latter is soluble in ether, and in spirit of turpentine, while the former is insoluble in ether, and but partially soluble in spirit of turpentine. It should seem to follow, that if the substance found lying under the rings be really the elements of wax, it under- goes som.e subsequent preparation after it is detached ; and that the bees, in short, are capable of impregnating it with matter, imparting to it whiteness and ductility, whereas in its unprepared state it is only fusible. Propolis. Wax is not the only material employed by bees in their architecture. Beside this, they make use of a brown, odoriferous, resinous substance, called propolis,^ more tenacious and extensible than wax, and well adapted for cementing and varnishing. It was strongly suspected by Reaumur that the bees collected the propolis from those trees which are known to produce a similar gummy resin, such as the poplar, the birch, and the willow ; but he was thrown into doubt by not being able to detect the bees in the act of procuring it, and by observing them to collect it where none of those trees, nor any other of the same description, grew. His bees also refused to make * Huber on Bees, p. 325. f From two Greek words, irpo iroXis, meaning be/ore the city, as the substance is principally applied to the projecting parts of the hive. iiiV£-Bi:ES. 105 »ise of bitumen, and other resinous substances, with which he supplied them, though Mr. Knight, as we shall atter- M'ards see, was more successful.* Long before the time of Reaumur, however, Mouffet, in his Insectarum llieatrum, quotes Cordus for the opi- nion that propolis is collected from the buds of trees, such as the poplar and birch ; and lleim says it is collected from the pine and fir.f lluber at length set the question at rest ; and his experiments and observa- tions are so interesting, that v.e shall give them in his own \^•ords : — " For many years," says he, "I had fruitlessly endea- voured to find them on trees producing an analogous sub- stance, though multitudes had been seen returning laden with it. " In July, some branches of the wild poplar, which had been cut since spring, with very large buds, full of a reddish, viscous, odoriferous matter, were brought to me, and I planted them in vessels before hives, in the way of the bees going out to forage, so that they could not be in- sensible of their presence. Within a quarter of an hour, they were visited by a bee, which separating the sheath of a bud with its teeth, drew out threads of the viscous substance, and lodged a pellet of it in one of the baskets of its limbs : from another bud it collected another pellet for the opposite limb, and departed to the hive. A second bee took the place of the former in a few minutes, following the same procedure. Young shoots of poplar, recently cut, did not seem to attract these insects, as their viscous matter had less consistence than the former.j: "Different experiments proved the identity of this substance with the propolis ; and now, having only to discover how the bees applied it to use, vre peopled a hive, so prepared as to fulfil our views. The bees, building upwards, soon reached the glass above ; but, * Phil. Trans, for 1807, p. 242. f Schirach, Hist, des Abeilles, p. 241. X Kirby and Spence observed bees very busy in collecting propolis from the tacamahaca tree CPopulus batsamifera) Introd., ii. 186. ^ VOL. I. r 106 INSECT ARCHITECTURE. unable to quit their habitation, on account of rain, they were three weeks without bringing home [)ropolis. Their combs remained perfectly white until the beginning of July, when the state of the atmosphere became more favourable for our observations. Serene, warm weather engaged them to forage, and they returned from the fields laden with a resinous gum, resembling a transparent jelly, and having the colour and lustre of the garnet. It was easily distinguished from the farinaceous pellets then col- lected by other bees. The workers bearing the propolis ran over the clusters, suspended from the roof of the hive, and rested on the rods supporting the combs, or some- times stopped on the sides of their dwelling, in expecta- tion of their companions coming to disencumber them of their burthen. We actually saw two or three arrive, and carry the propolis from off the limbs of each with their teeth. The upper part of the hive exhibited the most animated spectacle ; thither a multitude of bees resorted from all quarters, to engage in the predominant occupa- tion of the collection, distribution, and application of the propolis. Some conveyed that of which they had mi- loaded the purveyors in their teeth, and deposited it in heaps ; others hastened, before its hardening, to spread it out like a varnish, or formed it into strings, proportioned to the interstices of the sides of the hive to be filled up. Nothing could be more diversified than the operations carried on. " The bees, apparently charged with applying the pro- polis within the cells, were easily distinguished from the multitude of workers, by the direction of their heads to- wards the horizontal pane forming the roof of the hive, and on reaching it, they deposited their burthen nearly in the middle of intervals separating the combs : then they conveyed the propolis to the real place of its destination. They suspended themselves by the claws of the hind legs to points of support, afforded by the viscosity of the pro- polis on the glass ; and, as it were, swinging themselves backwards and forwards, brought the heap of this sub- stance nearer to the cells at each imjjulse. Here the bees employed their fore feet, which remained free, to sweep HIVK-BKES. 107 what the teeth Iiad detached, and to unite the fragments scattered over the glass, which recovered all its transpa- rency when the whole propolis was brought to the vici- nity of the cells. "After some of the bees had smoothed down and cleaned out the glazed cells, feeling the way with their antennse, one desisted, and having approached a heap of propolis, drew out a thread with its teeth. This being broken otf, it was taken in the claws of the fore feet, and the bee, re-entering the cell, immediately placed it in the angle of two portions that had been smoothed, in which operation the fore feet and teeth were used alternately ; but pro- bably proving too clumsy, the thread was reduced and polished ; and we admired the accuracy with which it was adjusted when the work was completed. The insect did not stop here : returning to the cell, it prepared other parts of it to receive a second thread, for which we did not doubt that the heap would be resorted to. Contrary to our expectation, however, it availed itself of the portion of the thread cut off on the former occasion, arranged it in the appointed place, and gave it all the solidity and finish of which it was susceptible. Other bees concluded the work which the first had begun ; and the sides of the cells were speedily secured with threads of propolis, while some were also put on the orifices ; but we could not seize the moment when they were varnished, though it may be easily conceived how it is done."* This is not the only use to which bees apply the pro- polis. They are extremely solicitous to remove such in- sects or foreign bodies as happen to get admission into the hive. When so light as not to exceed their powers, they first kill the insect with their stings, and then drag it out with their teeth. But it sometimes happens, as was first observed by Maraldi, and since by Reaumur and others, that an ill-fated snail creeps into the hive : this is no sooner perceived than it is attacked on all sides, and stung to death. But how are the bees to carry out so heavy a burthen ? Such a labour would be in vain. To prevent * Huber on Bees, p. 408. r2 108 IKSECT AKCUITKCTURE. the noxious sineli which would arise from its putrefaction, they immediately embalm it, by covering every part of its body with propolis, through which no effluvia can escape. When a snail with a shell gets entrance, to dis- pose of it gives much less trouble and expense to the bees. As soon as it receives the first wound from a sting, it natm'ally retires within its shell. In this case, the bees, instead of pasting it all over with propolis, content them- selves with gluing all round the margin of the shell, which is sufficient to render the animal for ever immoveably fixed. Mr. Knight, the learned and ingenious President of the Horticultural Society, discovered by accident an arti- ficial substance, more attractive than any of the resins experimentally tried by Reaumur, Having caused the decorticated part of a tree to be covered with a cement composed of bees'-wax and turpentine, he observed that this was frequented by hive-bees, who, finding it to be a very good propolis ready made, detached it from the tree with their mandibles, and then, as usual, passed it from the first leg to the second, and so on. When one bee had thus collected its load, another often came behind and despoiled it of all it had collected ; a second and a third load were frequently lost in the same manner ; and yet the patient insect pursued its operations without manifest- ing any signs of anger.* Probably the latter circum- stance, at which Mr. Knight seems to have been surprised, was nothing more than an instance of the division of labour so strikingly exemplified in every part of the eco- nomy of bees. It may not be out of place here to describe the appa- ratus with which the worker-bees are provided lor the pui'pose of carrying the propolis as well as the pollen of flowers to the hive, and which has just been alluded to in the observations of Mr. Knight. The shin or middle portion of the hind pair of legs is actually formed into a triangular basket, admirably adapted to this design. The bottom of this basket is composed of a sujooth, shining, * Philosophical Trans, for 18G7, p. 242, IiIVi:-SEKS. 109 Structure of the legs of the Bee f>.r carrying propolis a;id I'oUen, mag- nified . horn-like substance, hollowed out in the substance of the limb, and surrounded with a margin of strong and thickly- set bristles. Whatever materials, therefore, may be placed by the bee in the interior of this basket, are secured from falling out by the bristles around it, whose elasticity will even allow the load to be heaped beyond their points without letting it fall. In the case of propolis, when the bee is loading her singular basket, she first kneads the piece she has de- tached with her mandibles, till it becomes somewhat dry and less adhesive, as otherwise it would stick to her limbs. This preliminary process sometimes occupies nearly half an hour. She then passes it backwards by means of her feet to the cavity of her basket, giving it two or three pats to make it adhere ; and when she adds a second portion to the first, she often finds it necessary to pat it still harder. When she has procured as much as the basket will conveniently hold, she flies ofl" with it to the hive. THE BUILDIXG OF THE CELLS. The notion commonly entertained respecting glass hives is altogether erroneous. Those who are unacquainted 110 IXSECT ARCHITECTUKE. with bees imagine that, by means of a glass hive, all their proceedings may be easily watched and recorded; but it is to be remembered that bees are exceedingly averse to the intrusion of light, and their first operation in such cases is to close up every chink by which light can enter to disturb them, either by clustering together, or by a plaster composed of propolis. ^ It consequently requires considerable management and ingenuity, even with the aid of a glass hive, to see them actually at work. M. Huber employed a hive with leaves, which opened in the manner of a book ; and for some purposes he used a glass box, inserted in the body of the hive, but easily brought into view by means of screws. But no invention hitherto contrived is sufficient to ob- viate every difficulty. The bees are so eager to afford mutual assistance, and for this purpose so many of them crowd together in rapid succession, that the operations of individuals can seldom be traced. Though this crowding, however, appears to an observer to be not a little con- fused, it is all regulated with admirable order, as has been ascertained by Reaumur and other distinguished naturalists. When bees begin to build the hive, they divide them- selves into bands, one of which produces materials for the structure ; another works upon these, and forms them into a rough sketch of the dimensions and partitions of the cells. All this is completed by the second band, who examine and adjust the angles, remove the superfluous wax, and give the work its necessary perfection ; and a third band brings provisions to the labourers, who cannot leave their work. But no distribution of food is made to those whose charge, in collecting propolis and pollen, calls them to the field, because it is supposed they will hardly forget themselves ; neither is any allowance made to those who begin the architecture of the cells. Their province is very troublesome, because they are obliged to level and extend, as well as cut and adjust the wax to the dimensions required ; but then they soon obtain a dismission from this labour, and retire to the fields to regale themselves with food, and wear off their fatigue niVE-BEES. Ill with a more agreeable employment. Those who suc- ceed them, draw their mouth, their feet, and the ex- tremity of their body, several times over all the work, and never desist till the whole is polished and completed ; and as they frequently need refreshments, and yet are not permitted to retire, there are waiters always attend- ing, who serve them with provisions when they require them. The labourer who has an appetite, bends down his trunk before the caterer to intimate that he has an inclination to eat, upon which the other opens his bag of honey, and pours out a few drops ; these may be dis- tinctly seen rolling through the whole of his trunk, which insensibly swells in every part the liquor flows through. When this little repast is over, the labourer returns to his work, and his body and feet repeat the same motions as before.* Before they can commence building, however, when a colony or swarm migrates from the original hive to a new situation, it is necessary first to collect propolis, M'ith which every chink and cranny in the place where they mean to build may be carefully stopped up ; and secondly, that a quantity of wax be secreted by the wax-workers, to form the requisite cells. The secretion of wax, it would appear, goes on best when the bees are in a state of repose ; and the wax-workers, accordingly, suspend themselves in the interior in an extended cluster, like a curtain which is composed of a series of intertwined fes- toons or garlands, crossing each other in all directions, — the uppermost bee maintaining its position by laying hold of the roof with its fore-legs, and the succeeding one by laying hold of the hind legs of the first. " A person," says Reaumur, " must have been born devoid of curiosity not to take interest in the investigation of such wonderful proceedings." Yet Reaumur himself seems not to have understood that the bees suspended themselves in this manner to secrete wax, but merely, as he imagined, to recruit themselves by rest for renewing' their labours. The bees composing the festooned cur- * Spectacle de la Nature, tome i. 112 INSECT AK( lilTLCTLHr. tain are individually motionless ; but this curtain is, not- withstanding, kept moving- by the proceedings in the in- terior ; for the nurse-bees never form any portion of it, and continue their activity— a distinction with which lleauniur was unacquaintecL Curtain of W,ix w* rke-is ^eineiin'' wak. HlVS-UiiliS. 113 Altliough there are many thousand labourers in a hive, they do not commence foundations for combs in several places at once, but wait till an individual bee has selected a site, and laid the foundation of a comb, which serves as a directing mark for all that are to follow. Were we not expressly told by so accurate an observer as Huber, we might hesitate to believe that bees, though united in what appears to be a harmonious monarchy, are strangers to subordination, and subject to no discipline. Hence it is, that though many bees work on the same comb, they do not appear to be guided by any simultaneous impulse. The stimulus which moves them is successive. An in- dividual bee commences each operation, and several others successively apply themselves to accomplish the the same purpose. Each bee appears, therefore, to act individually, either as directed by the bees preceding it, or by the state of advancement in which it finds the work it has to proceed with. If there be anything like una- nimous consent, it is the inaction of several thousand v.orkers while a single individual proceeds to determine and lay down the foundation of the first comb. Reaumur regrets, that, though he could by snatches detect a bee at work in founding cells or perfecting their structure, his observations were generally interrupted by the crowding of other bees between him and the little builder. He was therefore compelled rather to infer the different steps of their procedure from an examination of the cells when completed, than from actual observation. The ingenuity of Huber, even under all the disadvantages of blindness, succeeded in tracing the minutest operations of the workers from the first waxen plate of the foundation, We think the narrative of the discoverer's experiments, as given by himself, will be more interesting than any abstract of it which we could furnish. " Having taken a large bell-shaped glass receiver, we glued thin wooden slips to the arch at certain intervals, because the glass itself was too smooth to admit of the bees supporting themselves on it. A swarm, consisting of some thousand workers, several hundred males, and a fertile queen, was introduced, and they soon ascended to f3 114 INSECT ARCHITECTURE. the top. Those first gaining the slips, fixed themselves there by the fore-feet ; others, scrambling up the sides, joined them, by holding their legs with their own, and they thus formed a kind of chain, fastened by the two ends to the upper parts of the receiver, and served as ladders or a bridge to the workers enlarging their num- ber. The latter were united in a cluster, hanging like an inverted pyramid from the top to the bottom of the hive. " The country then affording little hone}^, we pro- vided the bees with syrup of sugar, in order to hasten their labour. They crowded to the edge of a vessel con- taining it ; and, having satisfied themselves, returned to the group. We were now struck with the absolute re- pose of this hive, contrasted with the usual agitation of bees. Meanwhile, the nurse-bees alone went to forage in the countiy ; they returned with pollen, kept guard at the entrance of the hive, cleansed it, and stopped up its edges with propolis. The wax-workers remained m.o- tionless above fifteen hours : the curtain of bees, consist- ing always of the same individuals, assured us that none replaced them. Some hours later, we remarked that almost all these individuals had wax scales under the rings ; and next day this phenomenon was still more general. The bees forming the external layer of the cluster, having now somewhat altered their position, enabled us to see their bellies distinctly. By the projection of the wax scales, the rings seemed edged with white. The curtain of bees became rent in several places, and some commo- tion began to be observed in the hive. " Convinced that the combs would originate in the centre of the swarm, our whole attention was then di- rected towards the roof of the glass. A worker ati this time detached itself from one of the central festoons of the cluster, separated itself from the crowd, and, with its head, drove away the bees at the beginning of the row in the middle of the arch, turning round to form a space an inch or more in diameter, in which it might move freely. It then fixed itself in the centre of the space thus cleared. hive-bi:es. 115 " The worker now employing the pincers at the joint of one of the third pair of its limbs, seized a scale of wax projectine: from a ring-, and brought it forward to its mouth with the claws of its lore-legs, where it appeared Wax-worker laying the foundation of.the first Cell. in a vertical position. We remarked that, with its claws, it turned the wax in every necessary direction ; that the edge of the scale was immediately broken down, and the fragments having been accumulated in the hollow of the mandibles, issued forth like a very narrow ribbon, impregnated with a frothy liquid by the tongue. The tongue itself assumed the most varied shapes, and executed the most complicated operations, — being some- times flattened like a trowel, and at other times pointed like a pencil ; and, after imbuing the whole substance of the ribbon, pushed it forward again into the mandibles, whence it was drawn out a second time, but in an oppo- site direction. *' At length the bee applied these particles of wax to the vault of the hive, where the saliva impregnating them promoted their adhesion, and also communicated a white- ness and opacity which were wanting when the scales were detached from the rings. Doubtless, this process was to give the wax that ductility and tenacity belonging to its perfect state. The bee then separated those por- tions not yet applied to use with its mandibles, and with the same organs afterwards arranged them at pleasure. The founder bee, a name approjjriated to this worker, repeated the same operation, until all the fragments, worked up and impregnated with the fluid, were attached to the vault, when it repeated the preceding operations on the part of the scale yet kept apart, and again united to the rest what was obtained from it. A second and 116 I>SECT AECHITECTLIIE. third scale were similarly treated by the same bee ; yet the work was only sketched ; for the worker did nothing but accumulate the particles of wax together. Mean- while, the founder, quitting its position, disappeared amidst its companions. Another, with wax under the rings, succeeded it, which suspending itself to the same spot, withdrew a scale by the pincers of the hind legs, and passing it through its mandibles, prosecuted the work ; and taking care to make its deposit in a line with the former, it united their extremities. A third worker, de- taching itself from the interior of the cluster, now came and reduced some of the scales to paste, and put them Curlain of W. x-'voikei-s (see p. 1 12). iiive-ue;-:s. 117 neai' the materials accumulated by its companions, but not in a straight line. Another bee, apparently sensible of the defect, removed the misplaced wax before our eyes, and carrying it to the former heap, deposited it there, exactly in the order and direction pointed out. " From all these operations was produced a block of a rugged surface, hanging down from the arch, without any perceptible angle, or any traces of cells. It was a simple wall, or ridge, running in a straight line, and without the least inflection, two-thirds of an inch in length, about two-thirds of a cell, or two lines, high, and declining towards the extremities. We have seen other foundation walls from an inch to an inch and a half long, the form being always the same ; but none ever of greater height. " The vacuity in the centre of the cluster had per- mitted us to discover the first manoeuvres of the bees, and the art with which they laid the foundations of their edifices. However, it was filled up too soon for our sa- tisfaction ; for workers collecting on both faces of the wall obstructed our view of their further operations." * * Hubcr on Bee?, n. 358. ( 118 ) CHAPTER VI. Architecture of the Hive-bee continued — Form of the Cells. The obstruction of which M. Huber complains only operated as a stimulus to his ingenuity in contriving how he might continue his interesting observations. From the time of Pappus to the present day, mathematicians have applied the principles of geometry to explain the construction of the cells of a bee-hive ; but though their extraordinary regularity, and wonderfully selected form, had so often been investigated by men of the greatest talent, and skilled in all the refinements of science, the process by which they are constructed, involving also the causes of their regularity of form, had not been traced, till M. Huber devoted himself to the inquiry. As the wax-workers secrete only a limited quantity of wax, it is indispensably requisite that as little as possible of it should be consumed, and that none of it should be •wasted. Bees, therefore, as M. Reaumur well remarks,* have to solve this difficult geometrical problem : — a quan- tity of wax being given, to form of it similar and equal cells of a determinate capacity, but of the largest size in proportion to the quantity ot* matter employed, and dis- posed in such a manner as to occupy the least possible space in the hive. This problem is solved by bees in all its conditions. The cylindrical form would seem to be best adapted to the shape of the insect ; but had the cells been cylindrical, they could not have been applied to each other without leaving a vacant and superfluous space between every three contiguous cells. Had the cells, on the other hand, been square, or triangular, they might have been constructed without unnecessary vacancies ; but these forms would have both required more material * Reaumur, vol. v. p. 380. HIVE-BEES. 119 and been very unsuitable to the shape of a bee's body. The six-sided form of the cells obviates every objection ; and while it fulfils the conditions of the j)roblem, it is equally adapted with a cylinder to the shape of the bee. M. Reaumur further remarks, that the base of each cell, instead of forming a plane, is usually composed of three pieces in the shape of the diamonds on playing cards, and placed in such a manner as to form a hollow pyramid. This structure, it may be observed, imparts a greater degree of strength, and, still keeping the solution of the problem in view, gives a great capacity with the smallest expenditure of material. This has actually, in- deed, been ascertained by mathematical measurement and calculation. Maraldi, the inventor of glass hives, deter- mined, by minutely measuring these angles, that the greater were 109^ "28', and the smaller^TO^ 32'; and M. Reaumur, being desirous to know why these parti- cular angles are selected, requested M. Koenig, a skill ul mathematician (without informing him of his design, or telling him of Maraldi's researches), to determine by calculation, what ought to be the angle of a six-sided cell, with a concave ])yramidal base, formed of three similar and equal rhomboid plates, so that the least pos- sible matter should enter into its construction. By em- ploying what geometricians denominate the injitiitesimal calculus, M. Koenig found that the angles should be 109° 26' for the greater, and 70° 34' for the smaller, or about two-sixtieths of a degree, more or less, than the actual angles made choice of by bees. The equality of inclina- sion in the angles has also been said to facilitate the con- struction of the cells. M. Huber adds to these remarks, that the cells of the first row, by which the whole comb is attached to the roof of a hive, are not like the rest ; for, instead of six sides, they have only five, of which the roof forms one. The base, also, is in these different, consisting of three pieces on the face of the comb, and on the other side of two : one of these only is diamond shaped, while the other two are of an irregular four-sided figure. This ar- rangement, by bringing the greatest number of points in 120 INSECT ARCHITECTURE. contact with the interior surface, ensures the stability of the comb. Anaagemeni of Cells. It may, however, be said not to be quite certain, that Reaumur and others have not ascribed to bees the merit of ingenious mathematical contrivance and selection, when the construction of the cells may more probably originate in the form of their mandibles and other instru- ments employed in their operations. In the case of other insects, we have, both in the preceding and subsequent pages of this volume, repeatedly noticed, that they use their bodies, or parts thereof, as the standards of mea- surement and modelling ; and it is not impossible that bees may proceed on a similar principle. M. Huber replies to this objection, that bees are not provided with instruments corresponding to the angles of their cells ; for there is no more resemblance between these and the form of their mandibles, than between the chisel of the sculptor and the work which he produces. The head, he thinks, does not furnish any better explanation. He admits that the antennae are very flexible, so as to enable the insects to follow the outline of every object ; but concludes that neither their structure, nor that of the limbs and mandi- bles, are adequate to explain the form of the cells, though all these are employed in the operations of building, — the effect, according to him, depending entirely on the object which the insect proposes. We shall now follow M. Huber in the experiments HIVE-BEES. 121 which he contrived, in order to observe the operations of the bees subsequent to their laying a foundation for the first cell ; and we shall again quote from his own narrative : — " It appeared to me," he says, " that the only method of isolating the architects, and bringing them individually into view, would be to induce them to change the direc- tion of their operations and work upwards. " I had a box made twelve inches square and nine deep, with a moveable glass lid. Combs full of brood, honey, and pollen, were next selected from one of my leaf-hives, as containing what might interest the bees, and being cut into pieces a foot long, and four inches deep, they were arranged vertically at the bottom of the box, at the same intervals as the insects themselves usually leave between them. A small slip of wooden lath covered the upper edge of each. It was not pro- bable that the bees would attempt to found new combs on the glass roof of the box, because its smoothness pre- cluded the swarm from adhering to it ; therefore, if dis- posed to build, they could do so over the slips resting on the combs, which left a vacuity five inches high above them. As we had foreseen, the swarm with which this box was peopled established itself among the combs below. We then observed the nurse-bees displaying their natural activity. They dispersed themselves throughout the hive, to feed the young grubs, to clear out their lodg- ment, and adapt it for their convenience. Certainly, the combs, which were roughly cut to fit the bottom of the box, and in some parts damaged, appeared to them shapeless and misplaced ; for they speedily commenced their reparation. They beat down the old wax, kneaded it between their teeth, and thus formed binding materials to consolidate them. We were astonished beyond ex- pression by such a multitude of workers employed at once in labours to which it did not appear they should have been called, at their coincidence, their zeal, and their prudence. " But it was still more wonderful, that about half the numerous population took no part in the proceedings, i22 IKSECT AKCHITECTURE. remaining motionless, while the others fulfilled the func- tions required. The wax-workers, in a state of absolute repose, recalled our former observations. Gorged with the honey we had put within their reach, and continuing in this condition during twenty-four hours, wax was formed under their rings, and was now ready to be put in operation. To our great satisfaction, we soon saw a little foundation wall rising on one of the slips that we had prepared to receive the superstructure. No obstacle was offered to the progress of our observations ; and for the second time, we beheld both the undertaking of the founder-bee, and the successive labours of several wax- workers, in forming the foundation wall. Would that my readers could share the interest which the view of these architects inspired ! " This foundation, originally very small, was enlarged as the work required ; while they excavated on one side a hollow, of about the width of a common cell, and on the opposite surface two others somewhat more elongated. The middle of the single cell corresponded exactly to the partition separating the latter ; the arches of these exca- vations, projecting by the accumulation of wax, were converted into ridges in a straight line ; whence the cells of the first row were composed of five sides, con- sidering the slip as one side, and those of the second row, of six sides. Foundation-wall eiil.irjjed, and the Cl'IIs commenced. *' The interior conformation of the cavities, apparently, was derived from the position of their respective outlines. It seemed that the bees, endowed with an admirable delicacy of feeling, directed their teeth principally to the place where the wax was thickest ; that is, the parts where other workers on the opposite side had accumulated UIVJi-KEES. 123 it ; and this explains why the bottom of the cell is ex- cavated in an angular direction behind the projection on the sides of which the sides of the corresponding cells are to rise. The largest of the excavations, which was op- ])Osite to three others, was divided into three parts, while the excavations of the first row on the other face, applied against this one, were composed of only two. *' In consequence of the manner in which the excava- tions were opposed to each other, those of the second row, and all subsequent, partially applied to three cavi- ties, were composed of three equal diamond-shaped lo- zenges. I may here remark, that each part of the labour of bees appears the natural result of what has preceded it ; therefore, chance has no share in these admirable combinations. " A foundation wall rose above the slip like a minute vertical partition, five or six lines long, two lines high, but only half a line in thickness ; the edge circular, and the surface rough. Quitting the cluster among the combs, a nurse-bee mounted the slip, turned around the block, and visiting both sides, began to work actively in the middle. It removed as much wax with its teeth as might equal the diameter of a cOmmon cell ; and after kneading and moistening the particles, deposited them on the edge of the excavation. This insect having laboured some seconds, retired, and was soon replaced by another; a third continued the work, raising the margin of the edges, now projecting from the cavity, and with assistance of its teeth and feet fixing the particles, so as to give these edges a straighter form. More than twenty bees succes- sively participated in the same work ; and when the ca- vity was little above a line and a half in height, though equalling a cell in width, a bee left the swarm, and after encircling the block commenced its operations on the opposite face, where yet untouched. But its teeth acting only on one half of this side, the hollow which it formed was opposite to only one of the slight prominences bor- dering the first cavity. Nearly at the same time another worker began on the right of the face that had been un- touched, wherein both were occupied in forming cavities, 124 INSECT ARCHITECTURE. which may be designed the second and third ; and they also were replaced by substitutes. These two latter ca- vities were separated only by the common margin, framed of particles of wax withdrawn from them ; which margin corresponded with the centre of the cavity on the oppo- site surface. The foundation wall itself was still of in- sufficient dimensions to admit the full diameter of a cell : but while the excavations were deepened, wax-workers, extracting their scales of wax, applied them in enlarging its circumference ; so that it rose nearly two lines further around the circular arch. The nurse-bees, which ap- peared more especially charged with sculpturing the cells, being then enabled to continue their outlines, pro- longed the cavities, and heightened their margins on tl^e new addition of wax. " The arch, formed by the edge of each of these ca- vities, was next divided as by two equal chords, in the line of which the bees formed stages or projecting bor- ders, or margins meeting at an obtuse angle ; the cavities now had four margins, two lateral and perpendicular to the supporting slip, and two oblique, which were shorter. " Meantime, it became more difficult to follow the operations of the bees, from their frequently interposing their heads between the eye of the observer and the bot- tom of the cell ; but the partition, whereon their teeth laboured, had become so transparent, as to expose what passed on the other side. " The cavities of which we speak, formed the bottom of the first three cells ; and while the bees engaged were advancing them to perfection, other workers commenced sketching a second row of cells above the first, and partly behind those in front — for, in general, their labour pro- ceeds by combination. We cannot say, ' When bees have finished this cell, they will begin new ones;' but, ' while particular workers advance a certain portion, we are certain that others will carry on the adjacent cells.' Further, the work begun on one face of the comb is already the commencement of that which is to follow on the reverse. All this depends on a reciprocal relation. lilVE-IiELs. 125 or a mutual connexion of the parts, rendering' the whole subservient to each other. It is undoubted, therefore, that slight irregularities on the front will affect the form of the cells on the back of the comb." * When they have in this manner worked the bottoms of the first row of cells into the required forms, some of the nurse-bees finish them by imparting a sort of polish, while others proceed to cut out the rudiments of a second row from a fresh wall of wax which has been built in the meanwhile by the wax-workers, and also on the opposite side of this wall; for a comb of cells is always double, being arranged in two layers, placed end to end. The cells of this second row are engrafted on the borders of cavities hollowed out in the wall, being founded by the nurse-bees, bringing the contour of all the bottoms, which is at first unequal, to the same level ; and this level is ke}»t uniform in the margins of the cells till they are completed. At first sight, nothing appears more simple than adding wax to the margins ; but from the inequalities occasioned by the shape of the bottom, the bees must accumulate M'ax on the depressions, in order to bring them to a level. It follows accordingly that the surface of a new comb is not quite fiat, there being a pro- gressive slope produced 'as the work proceeds, and the comb being therefore in the form of a lens, the thickness decreasing towards the edge, and the last formed cells being shallov.er or shorter than those preceding them. So long as there is room for the enlargement of the comb, this thinning of its edge may be remarked ; but as soon as the space within the hive prevents its enlargement, the cells are made equal, and two flat and level surfaces are produced. M. Huber observed, that while sketching the bottom of a cell, before there was any upright margin on the reverse, their pressure on the still soft and flexible wax gave rise to a projection, v.hich sometimes caused a breach of the partition. This, however, was soon repaired, but a slight prominence always remained on the opposite sur- * Huber on Bies, p. 368. 126 INSECT ARCHIfECTUEE. face, to the right and left of which they placed them- selves, to begin a new excavation ; and the}' heaped up part of the materials between the two flutings formed by their labour. The ridge thus formed becomes a guide to the direction which the bees are to follow for the ver- tical furrow of the front cell. We have already seen that the first cell determines the place of all that succeed it, and two of these are never, in ordinary circumstances, begun in dilierent parts of the hive at the same time, as is alleged by some early writers. When some rows of cells, however, have been com- pleted in the first comb, two other foundation walls are begun, one on each side of it, at the exact distance of one-third of an inch, which is sufhcient to allow two bees employed on the opposite ceils to pass each other without jostling. These new walls are also parallel to tlie former ; and two more are afterwards begun exterior to the se- cond, and at the same parallel distance. The combs are uniformly enlarged, and lengthened in a progression pro- portioned to the priority of their origin ; the middle comb being always advanced beyond the two adjoining ones by several rows of cells, and these again beyond the ones exterior to them. Did the bees lay the foundations of all their combs at the same time, they would not find it easy to preserve parallelism and an equality in their distances. It may be remarked further, that beside the vacancies of half an inch between the cells, which form what we call the highways of the community, the combs are pierced in several places with holes which serve as postern-gates for easy communication from one to another, to prevent loss of time in going round. The equal dis- tance between the combs is of more importance to the welfare of the hive than might at first appear ; for were they too distant, the bees would be so scattered and dis- persed, that they could not reciprocally communicate the heat indispensable for hatching the eggs and rearing the young. If the combs, on the other hand, were closer, the bees could not traverse the intervals with the freedom necessary to facilitate the work of the hive. On the ap- proach of winter, they sometimes elongate the cells which IIIVE-BEES. 127 contain honey, and thus contract the intervals between the combs. But this expedient is in jjreparation lor a season when it is important to have copious magazines, and when, their activity being relaxed, it is unnecessary for their communications to be so spacious and free. On the return of spring, the bees hasten to contract the elongated cells, that they may become fit for receiving the eggs which the queen is about to deposit, and in this manner they re-establish the regular distance.* We are indebted to the late Dr. Barclay of Edinburgh, well known as an excellent anatomist, for the discovery that each cell in a honeycomb is not simply composed of one wall, but consists of two. We shall give the account of his discovery in his own words : — *' Having inquired of several naturalists whether or not they knew any author who had mentioned that the par- titions between the cells of the honeycomb were double, and ^^ hether or not they had ever remarked such a struc- ture themselves, and they having answered in the nega- tive, I now take the liberty of presenting to the Society pieces of honeycomb, in w hich the young bees had been reared, upon breaking which, it will be clearly seen that the partitions between difierent cells, at the sides and the base, are all double; or, in other words, that each cell is a distinct, separate, and in some measure an in- dependent structure, agglutinated only to the neighbour- ing cells ; and that when the agglutinating substance is destroyed, each cell may be entirely separated from the rest. " I have also some specimens of the cells formed by wasps, which show that the partitions between them are also double, and that the agglutinating substance between them is more easily destroyed than that between the cells of the bee."t IKKEGULARITIES IX THEIR WORKMANSHIP. Though bees, however, work with great uniformity * Huber on Bees, p. 220. f Memoirs of the Wernerian Nat. Hist. Soc. vol. ii. p. 2G0. 128 INSECT ARCHITECTURE, Avhen circumstances favour their operations, they may be compelled to vary their proceeding-s. M. Huber made several ingenious experiments of this kind. The follow- ing, mentioned by Dr. Bevan, was accidental, and oc- curred to his friend Mr. Walond. " Inspecting his bee- boxes at the end of October, 1817, he perceived that a centre comb, burthened with honey, had separated from its attachments, and v.as leaning against another comb so as to prevent the passage of the bees betv.een them. This accident excited great activity in the colony ; but its nature could not be ascertained at the time. At the end of a week, the weather being cold, and the bees clustered together, Mr. Walond observed, through the window of the box, that they had constructed two hori- zontal pillars betwixt the combs alluded to ; and had removed so much of the honey and wax from the top of each as to allow the passage of a bee : in about ten days more there Mas an uninterrupted thoroughfare ; the de- tached comb at i(s upper part had been secured by a strong barrier, and fastened to the window with the spare wax. This being accomplished, the bees removed the horizontal pillars first constructed, as being of no further use."* A similar anecdote is told by M. Huber. "During the winter," sa^^s he, " a comb in one of my bell-glass hives, having been originally insecure, fell down, but preserved its position parallel to the rest. The bees were unable to fill up the vacuity left above it, because they do not build combs of old v.ax, and none new could be then obtained. At a more favourable season they would have ingrafted a new comb on the old one ; but now their provision of honey could not be spared for the elaboration of this substance, which induced them to ensure the stability of the comb by another process. " Crowds of bees taking wax from the lower part of other combs, and even gnawing it from the suriace of the orifices of the deepest cells, they constructed so many irregular pillars, joists, or buttresses, between the sides '■'■ Bevan on Bees, p. 326. HIVE-BEES. 129 of the fallen comb, and others on the glass of the hive. All these were artificially adapted to localities. Neither did they confine themselves to repairing the accidents which their works had sustained. They seemed to profit by the warning to guard against a similar casualty. '* The remaining combs were not displaced ; therefore, while solidly adhering by the base, we were greatly sur- prised to see the bees strengthen their principal fixtures with old wax. They rendered them much thicker than before, and fabricated a number of new connexions, to unite them more firmly to each other and to the sides of their dwelling. All this passed in the middle of January, a time that these , insects commonly keep in the upper part of their hive, and when work is no longer season^ able.--'* M. Huber the younger shrewdly remarks, that the tendency to symmetry observable in the architecture of bees does not hold so much in small details as in the whole work, because they are sometimes obliged to adapt themselves to particular localities. One irregularity leads on to another, and it commonly arises from mere accident, or from design on the part of the proprietor of the bees. By allowing, for instance, too little interval between the spars for receiving the foundation of the combs, the struc- ture has been continued in a particular direction. The bees did not at first appear to be sensible of the defect, though they afterwards began to suspect their error, and were then observed to change their line of work till they gained the customary distance. The cells havino- been by this change of direction in some degree curved, the new ones which were commenced on each side of it, by being built everywhere parallel to it, partook of the same curvature. But the bees did not relish such approaches to the 'Mine of beauty," and exerted themselves to brino- their buildings again into the regular form. In consequence of several irregularities which they wished to correct, the younger Huber has seen bees de- part from their usual practice, and at once lay on a spar * Huber on Bee?, p. 416. VOL. I. Q 130 IXSECT AKCHITECTURE. two foundation walls not in the same line. They could consequently neither be enlarged without obstructing both, nor from their position could the edges unite had they been prolonged. The little architects, however, had recourse to a very ingenious contrivance : they curved the edges of the two combs, and brought them to unite so neatly that they could be both prolonged in the same line with ease ; and when carried to some little distance, their surface became quite uniform and level. " Having seen bees," says the elder Huber, '* work both up and down, I wished^ to try to investigate whether we could compel them to construct their combs in any other direction. We endeavoured to puzzle them with a hive glazed above and below, so that they had no place of support but the upright sides of their dwelling ; but, betaking themselves to the upper angle, they built their combs perpendicular to one of these sides, and as regularly as those which they usually build under a horizontal sur- face. The foundations were laid on a place which does not serve naturally for the base, yet, except in the difference of direction, the first row of cells resembled those in or- dinary hives, the others being distributed on both faces, while the bottoms alternately corresponded with the same symmetry. I put the bees to a still greater trial. As they now testified their inclination to carry their combs, by the shortest way, to the opposite side of the hive (for they prefer uniting them to wood, or a surface rougher than glass), I covered it with a pane. Whenever this smooth and slippery substance was interposed between them and the wood, they departed from the straight line hitherto followed, and bent the structure of their comb at a right angle to what was already made, so that the pro- lono-ation of the extremity might reach another side of the hive, which had been left free. x " Varying this experiment in several ways, I saw the bees constantly change the direction of their conibs, when I presented to them a surface too smooth to admit of their clustering on it. They always sought the wooden sides. I thus compelled them to curve the combs in the strangest shapes, by placing a pane at a certain distance from their HIVE-BEES. 131 edges. These results indicate a degree of instinct truly wonderful. They denote even more than instinct : for glass is not a substance against which bees can be warned by nature. In trees, their natural abode, there is nothing that resembles it, or with the same polish. The most singular part of their proceeding is changing the direction of the work before arriving at the surface of the glass, and while yet at a distance suitable for doing so. Do they anticipate the inconvenience which would attend any other mode of building ? No less curious is the plan adopted by the bee for producing an angle in the combs : the wonted fashion of their work, and the dimensions of the cells, must be altered. Therefore, the cells on the upper or convex side of the combs are enlarged ; they are constructed of three or four times the width of those on the opposite surface. How can so many insects, oc- cupied at once on the edges of the combs, concur in giving them a common curvature from one extremity to the other '? How do they resolve on establishing cells so small on one side, while dimensions so enlarged are be- stowed on those of the other ? And is it not still more singular, that they have the art of making a correspond- ence between cells of such reciprocal discrepance ? The bottom being common to both, the tubes alone assume a taper form. Perhaps no other insect has afforded a more decisive proof of the resources of instinct, when com- pelled to deviate from the ordinary course. "But let us study them in their natural state, and there we shall find that the diameter of their cells must be adapted to the individuals which shall be bred in them. The cells of males have the same figure, the same number of lozenges and sides, as those of workers, and angles of the same size. Their diameter is 3^ lines, while those of workers are only 2|. " It is rarely that the cells of males occupy the higher part of the combs. They are generally in the middle or on the sides, where they are not isolated. The manner in which they are surrounded by other cells alone can explain how the transition in size is effected. When the cells of males are to be fabricated under those g2 132 INSECT ARCIIITECTUBE. of workers, the bees make several rows of intermediate cells, whose diameter augments progressively, until gaining that proportion proper to the cells required ; and in returning to those of workers, a lowering is observed in a manner corresponding. "Bees, in preparing the cells of males, previously establish a block or lump of wax on the edge of their comb, thicker than is usually employed for those of workers. It is also made higher, otherwise the same order and symmetry could not be preserved on a larger scale. " Several naturalists notice the irregularities in the cells of bees as so many defects. What would have been their astonishment had they observed that part of them are the result of calculation ? Had they followed the imperfection of their organs, some other means of com- pensating them would have been granted to the insects. It is much more surprising that they know how to quit the ordinary route, when circumstances demand the con- struction of enlarged cells; and, after building thirty or forty rows of them, to return to the proper proportions from which they have departed by successive reductions. Bees also augment the dimensions of their cells when there is an opportunity for a great collection of honey. Not only are they then constructed of a diameter much exceeding that of the common cells, but they are elon- gated throughout the whole space admitting it. A great portion of irregular comb contains cells an inch, or even an inch and a half, in depth. " Bees, on the contrary, sometimes are induced to shorten their cells. When wishing to prolong an old comb, whose cells have received their full dimensions, they gradually reduce the thickness of its edges, by gnawing down the sides of the cells, until they restore it to its original lenticular form. They add a waxen block around the whole circumference, and on the edge of the comb construct pyramidal bottoms, such as those fabricated on ordinary occasions. It is a certain fact, that a comb never is exiended in any direction unless the bees have thinned the edges, which are diminished HIVE-BEES. 133 throughout a sufficient space to remove any angular pro- jection. ** The law which obliges these insects partly to demo- lish the cells on the edges of the comb before enlarging it, unquestionably demands more profound investigation. How can we account for instinct leading them to undo what they have executed with the utmost care ? The wonted regular gradation, which may be necessary for new cells, subsists among those adjoining the edges of a comb recently constructed. But afterwards, when those on the edge are deepened like the cells of the rest of the surface, the bees no longer preserve the decreasing grada- tion which is seen in the new combs."* THE riNISHING OF THE CELLS. While the cells are building, they appear to be of a dull white colour, sol't, even, though not smooth, and translucent ; but in a few days they become tinged with yellovv, particularly on the interior surface ; and their edges, from being thin, uniform, and yielding, become thicker, less regular, more heavy, and so firm that they will bend rather than break. New combs break on the slightest touch. There is also a glutinous substance ob- servable around the orifices of the yellow cells, of reddish colour, unctuous, and odoriferous. Threads of the same substance are applied all around the interior of the cells^ and at the summit of their angles, as if it were for the purpose of binding and strengthening the walls. These yellow cells also require a much higher temperature of water to melt them than the white ones. It appeared evident, therefore, that another substance, different from wax, had been employed in varnishing the orifices and strengthening the interior of the cells. M. Iluber, by numerous experiments, ascertained the resi- nous threads lining the cells, as well as the resinous substance around their orifice, to be propolis ; for he traced them, as we mentioned in our account of pro- polis, from the poplar buds where they collected it, and * Huber on Bees, p. 391. 134 INSECT AKCHITECTURE. saw them apply it to the cells ; but the yellow colour is not imparted by propolis, to which it bears no analogy. We are, indeed, by no means certain what it is, though it was proved by experiment not to arise from the heat of the hives, nor from emanations of honey, nor from particles of pollen. Perhaps it may be ascribed to the bees rubbing their teeth, feet, and other parts of their body, on the surfaces where they seem to rest ; or to their tongue (haustellum) sweeping from right to left like a fine pliant pencil, when it appears to leave some sprinkling of a transparent liquid. Beside painting and varnishing their cells in this man- ner, they take care to strengthen the weaker parts of their edifice by means of a mortar composed of propolis and wax, and named pissoceros* by the ancients, who first observed it, though Reaumur was somewhat doubtful respecting the existence of such a composition. We are indebted to the shrewd observations of Huber for a re- concilement of the Roman and the French naturalists. The details which he has given of his discovery are per- haps ihe most interesting in his delightful book. ** Soon," he says, " after some new combs had been finished in a hive, manifest disorder and agitation pre- vailed among the bees. They seemed to attack their own works. The primitive cells, whose structure we had ad- mired, w^ere scarcely recognizable. Thick and massy walls, heavy, shapeless pillars, were substituted for the slight partitions previously built with such regularity. The substance had changed along with the form, being composed apparently of wax and propolis. From the perseverance of the workers in their devastations, we suspected that they proposed some useful alteration of their edifices ; and our attention was directed to the cells least injured. Several were yet untouched ; but the bees soon rushed precipitately on them, destroyed the tubes, broke down the wax, and threw all the fragments about. But we remarked, that the bottom of the cells of the first row were spared ; neither were the corresponding parts '" From two Greek words, signifying pitch and wax. mVii-B£ES. 135 on both faces of the comb demolished at the same time. The bees laboured at them alternately, leaving some of the natural supports, otherwise the comb would have fallen down, which was not their object: they wished, on the contrary, to provide it a more solid base, and to secure its union to the vault of the hive, with a substance whose adhesive properties infinitely surpassed those of wax. The propolis employed on this occasion had been deposited in a mass over a cleft of the hive, and had hard- ened in drying, which probably rendered it more suitable for the purpose. But the bees experienced some difficulty in making any impression on it ; and we thought, as also had appeared to M. de Reaumur, that they softened it with the same frothy matter from the tongue which they use to render wax more ductile. " We very distinctly observed the bees mixing fragments of old wax with the propolis, kneading the two substances together to incorporate them ; and the compound was em- ployed in rebuilding the cells that had been destroyed. But they did not now follow their ordinary rules of archi- tecture, for they were occupied by the solidity of their edifices alone. Night intervening, suspended our observa- tions, but next morning confirmed what we had seen. " We find, therefore, that there is an epoch in the labour of bees, when the upper foundation of their combs is constructed simply of wax, as Reaumur believed; and that, after all the requisite conditions have been attained, it is converted to a mixture of wax and propolis, as remarked by Pliny so many ages before us. Thus is the apparent contradiction between these two great naturalists explained. But this is not the utmost extent of the fore- sight of these insects. When they have plenty of wax, they make their combs the full breadth of the hive, and solder them to the glass or wooden sides, by structures more or less approaching the form of cells, as circum- stances admit. But should the supply of wax fail before they have been able to give sufficient diameter to the combs whose edges are rounded, large intervals remain between them and the upright sides of the hive, and they are fixed only at the top. Therefore, did not the bees provide against it, by constructing great pieces of Avax 136 INSECT ARCIIITECTDRE. mixed with propolis, in the intervals, they might be borne down by the weight of the honey. These pieces are ot* irregular shape, strangely hollowed out, and their cavities void of symmetry."* It is remarked by the lively Abbe la Pluche, that the foundations of our houses sink with the earth on which they are built, the walls begin to stoop by degrees, they nod with age, and bend from their perpendicular ; — lodgers damage everything, and time is continually intro- ducing some new decay. The mansions of bees, on the contrary, grow stronger the oftener they change inha- bitants. Every bee-grub, before its metamorphosis into a nymph, fastens its skin to the partitions of its cell, but in such a manner as to make it correspond with the lines of the angles, and without in the least disturbing the re- gularity of the figure. During summer, accordingly, the same lodging may serve for three or four grubs in succes- sion ; and in the ensuing season it may accommodate an equal number. Each grub never fails to fortify the panels of its chamber by arraying them with its spoils, and the contiguous cells receive a similar augmentation from its brethren.! Reaumur found as many as seven or eight of these skins spread over one another : so that all the cells being incrusted with six or seven coverings, well dried and cemented with propolis, the whole fabric daily ac- quires a new degree of solidity. It is obvious, however, that by a repetition of this pro- cess the cell might be rendered too contracted ; but in such a case the bees know well how to proceed, by turn- ing the cells to other uses, such as magazines for bee-bread and honey. It has been remarked, however, that in the hive of a new swarm, during the months of July and Au- gust, there are fewer small bees or nurse-bees than in one that has been tenanted four or five years. The workers, in- deed, clean out the cell the moment that a young bee leaves its cocoon, but they never detach the silky film which it has previously spun on the walls of its cell. But though honey is deposited after the young leave the cells, the * Huber en Bees, p. 415. f Sj.ectacle de la Nature, vol. I. mVE-BEE3. 137 reverse also happens ; and accordingly, when bees are bred in contracted cells, they are by necessity smaller, and constitute, in fact, the important class of nurse-bees. We are not disposed, however, to go quite so far as an American periodical writer, who says, " Thus we see that the contraction of the cell may diminish the size of a bee, even to the extinction of life, just as the contraction of a Chinese shoe reduces the foot even touselessness."* We know, on the contrary, that the queen bee will not deposit eggs in a cell either too snuill or too large for the proper rearing of the young. In the case of large cells, M. Huber took advantage of a queen that was busy depositing the eggs of workers, to remove all the common cells adapted for their reception, and left only the large cells appro- priated for males. As this was done in June, when bees are most active, he expected that they would have imme- diately repaired the breaches he had made ; but to his great surprise they did not make the slightest movement for that purpose. In the meanwhile the queen, being oppressed by her eggs, was obliged to drop them about at random, preferring this to depositing them in the male cells, which she knew to be too large. At length she did deposit six eggs in the large cells, which were hatched, as usual, three days after. The nurse-bees, however, seemed to be aware that they could not be reared there, and, though they supplied them with food, did not attend to them regularly. M. Huber found that they had been all removed from the cells during the night, and the busi- ness both of laying and nursing was at a complete stand for twelve days, when he supplied them again with a comb of small cells, which the queen almost immediately filled with eggs, and in some cells she laid five or six. The architecture of the hive, which we have thus de- tailed, is that of bees receiving the aid of human care, and having external coverings of a convenient form, prepared for their reception. In this country bees are not found in a wild state ; though it is not uncommon for swarms to * North American Rev. Oct. 1828, p. 355. G 3 138 INSECT ARCHITECTURE. stray from their proprietors. But these stray swarms do not spread colonies through our woods, as they arc said to do in America. In the remoter parts of that continent there are no wild bees. They precede civilization ; and thus when the Indians observe a swarm they say, " The white man is coming." There is evidence of bees having abounded in these islands, m the earlier periods of our history ; and Ireland is particularly mentioned by the Venerable Bede as being "rich in milk and honey."* The hive-bee has formed an object of economical culture in Europe at least for two thousand years ; and Varro describes the sort of hives used in his time, 1870 years ago. We are not aware, however, that it is now to be found wild in the milder clime of Southern Europe, any more than it is in our own island. The w ild bees of Palestine principally hived in rocks. " He made him," says Moses, " to suck honey out of the rock."t " With honey out of the rock," says the Psalmist, " should I have satisfied thee."t In the caves of Salsette and Elephanta, at the present day, they hive in the clefts of the rocks and the recesses among the fis- sures, in such numbers, as to become very troublesome to visiters. Their nests hang in innumerable clusters. § We are told of a little black stingless bee found in the island of Guadaloupe, which hives in hollow trees or in the cavities of rocks by the sea-side, and lays " up honey in cells about the size and shape of pigeons' eggs. These cells are of a black or deep violet colour, and so joined together as to leave no space between them. They hang in clusters almost like a bunch of grapes." || The follow- ing are mentioned by Lindley as indigenous to Brazil. " On an excursion towards Upper Tapagippe," says he, " and skirting the dreary woods which extend to the in- terior, I observed the trees more loaded with bees' nests than even in the neighbourhood of Porto Seguro. They consist of a ponderous shell of clay cemented similarly to * " Hlbernia dives lactis ac mellis insula.' • — Beda, Hist. Eccles. i. 7. f Deut. xxxii. 13. % Psalm Ixxxi. 16. § Forbes, Orieu. Mem. i. || Amer. Q. Rev. iii. p. 383. HIVE-BEES. 139 martins' nests, swelling from high trees about a foot thick, and forming an oval mass full two feet in diameter. When broken, the wax is arranged as in our hives, and the honey abundant."* Captain Basil Hall found in South America the hive of a honey-bee very ditiiarent from the Brazilian, but nearly allied to, if not the same as, that of Guadaloupe. " The hive we saw opened," he says, " was only partly filled, which enabled us to see the economy of the inte- rior to more advantage. The honey is not contained in the elegant hexagonal cells of our hives, but in wax bags, not quite so large as an egg. These bags or bladders are hung round the sides of the hive, and appear about half full ; the quantity being probabl}^ just as great as the strength of the wax will bear without tearing. Those near the bottom, being better supported, are more filled than the upper ones. In the centre of the lower part of the hive we observed an irregularly-shaj^ed mass of comb, furnished with cells like those of our bees, all containing young ones in such an advanced state, that, when we broke the comb, and let them out, they flew merrily away." Clavigero, in his ' History of Mexico,' evidently describing the same species of bee, says it abounds in Yucatan, and makes the honey of Estabentum, the finest in the world, and which is taken every two months. He mentioned another species of bee, smaller in size, and also without a sting, which forms its nest of the shaj^e of a sugarloaf, and as large or larger. These are suspended from trees, particularly from the oak, and are much more populous .than our common hives. Wild hone3^-bees of some species appear also to abound in Africa. jNIr. Park, in his second volume of travels, tells us that some of his associates imprudently attempted to rob a numerous hive of its honey, when the exaspe- rated bees, rushing out to defend their property, attacked their assailants with great fury, and quickly compelled the whole company to fly. * Roy. Mil. Chron. quoted in Kiiby and Spence. 140 IKSECT ARCHITECTURE, At the Cape of Good Hope the bees themselves must be less formidable, or more easily managed, as their hives are sought for with avidity. Nature has there provided man with a singular and very efficient assistant in a bird, most appropriately named the honey-guide {Indicator major, Vieillot ; Cuculus indicator, Latham). The honey-guide, it is said, so far from being alarmed at the presence of man, appears anxious to court his acquaint- ance, and flits from tree to tree with an expressive note of invitation, the meaning of which is well known both to the colonists and the Hottentots. A person thus in- vited by the honey-guide seldom refuses to follow it onward till it stops, as it is certain to do, at some hollow tree containing a bee-hive, usually well stored with honey and wax. It may be that the bird finds itself inadequate to the attack of a legion of bees, or to penetrate into the interior of the hive, and is thence led to invite an agent more powerful than itself. The person invited, indeed, always leaves the bird a share of the spoil, as it would be considered sacrilege to rob it of its due, or in any way to injure so useful a creature. The Americans, who have not the African honey- guide, employ several well-known methods to track bees to their hives. One of the most common though inge- nious modes is to place a piece of bee-bread on a flat surface, a tile for instance, surrounding it with a circle of •wet white paint. The bee, whose habit it is always to alight on the edge of any plane, has to travel through the paint to reach the bee-bread. When, therefore, she flies oflT, the observer can track her by the white on her body. The same operation is repeated at another place, at some distance from the first, and at right angles to the bee-line just ascertained. The position of the hive is easily determined, for it lies in the angle made by the intersection of the bee lines. Another method is de- scribed in the Philosophical Transactions for 1721. The bee-hunter decoys, by a bait of honey, some of the bees into his trap, and when he has secured as many as he judges will suit his purpose, he incloses one in a tube, and, letting it fly, marks its course by a pocket compass. HIVE-BEES. 141 Departing to some distance, he liberates another, observes its course, and in this manner determines the position of the hive, upon the principle already detailed. These methods of bee-hunting depend upon the insect's habit of always flying in a right line to its home. Those who have read Cooper's tale of the ' Prairie ' must well remember the character of the bee-hunter, and the expres- sion of " lining a bee to its hive." In reading these and similar accounts of the bees of distant parts of the world, we must not conclude that the descriptions refer to the same species as the common- honey-bee. There are numerous species of social bees^ which, while they differ in many circumstances, agree in the practice of storing up honey, in the same way as we have numerous species of the mason-bee and of the humble-bee. Of the latter Mr. Stephens enumerates no. less than forty-two species indigenous to Britain. ( 142 ) CHAPTER YII. Carpentry of Tree-hoppers and Saw-flies. The operations of an insect in boring into a leaf or a bud to form a lodgment for its eggs appear very simple. The tools, however, by which these effects are per- formed are very complicated and curious. In the case of gall-flies (Cynips), the o}>eration itself is not so re- markable as its subsequent chemical effects. These effects are so different from any others that may be classed under the head of Insect Architecture, that we shall reserve them for the latter part of this volume ; although, with reference to the use of galls, the protec- tion of eggs and larvae, they ought to find a place here. We shall, however, at present confine ourselves to those which simply excavate a nest, without producing a tumour. The first of these insects which we shall mention is celebrated for its song, by the ancient Greek poets, under the name of Tettix. The Romans called it Cicada, which we sometimes, but erroneously, translate " grass- hopper ;" for the gi'asshoppers belong to an entirely different order of insects. We shall, therefore, take the liberty of calling the Cicadge Treehoppers^ to which the cuckoo-spit insect {Tettigonia spumaria, Oliv.) is allied ; but there is only one of the true Cicadas hitherto ascer- tained to be British, namely, the Cicada hcmmatodes (Lixx.), which was discovered in the New Forest, Hampshire, by Mr. Daniel Bydder. jNI. Reaumur was exceedingly anxious to study the economy of those insects ; but they not being indi- genous in the neighbourhood of Paris, he commissioned his friends to send him some from more southern latitudes, and he procured in this way specimens not only from the TREE-HOPPERS. 143 South of France and from Italy, but also from Egypt. From these specimens he has given the best account of them yet published ; for though, as he tells us, he had never had the pleasure of seeing one of them alive, the more interesting parts of their structure can be studied as well in dead as in living specimens. We ourselves pos- sess several specimens from New Holland, upon which we have verified some of the more interesting observations of Reaumur. Virgil tells us, that in his time " the cicadas burst t very shrubs with their querulous music ;" * but we m well suppose that he was altogether unacquainted wit| the singular instrument by means of which they can, n^ poeticall}^, but actually, cut grooves in the branches the select for depositing their eggs. It is the male, as in th case of birds, which fills the woods with his song ; whil i the female, though mute, is no less interesting to th < naturalist on account of her curious ovipositor. Thi . instrument, like all those with which insects are furnishec by nature for cutting, notching, or piercing, is compose( of a horny substance, and is also considerably larger thaT > the size of the tree-hopper would proportionally indicf* It can on this account be partially examined w;tMecc, microscope, being, in some of the larger species, no * than five lines t in length. -e- The ovipositor, or auger {tariere)^ as Reaumur calls it, is lodged in a sheath which lies in a groove of the termi- nating ring of the belly. It requires only a very slight pressure to cause the instrument to protrude from its sheath, when it appears to the naked eye to be of equal thickness throughout, except at the point, where it is somewhat enlarged and angular, and on both sides finely indented with teeth. A more minute examination of the sheath demonstrates that it is composed of two horny pieces slightly curved, and ending in the form of an elongated spoon, the concave part of which is adapted to receive the convex end of the ovipositor, * "Cautu querulae rumpent arbusta cicadae." Georg. iii, 328. f A line is about the twelfth part of an inch. 144 IKSECT ARCHITECTURE. When the protruded instrument is further examined "with a microscope, the denticulations, nine in number on each side, appear strong, and arranged with great sym- metry, increasing in fineness towards the point, where there are three or four very small ones, beside the nine that are more obvious. The magnifier also shows that the instrument itself, which appeared simple to the naked eye, is in fact composed of three diflfierent pieces, two exterior armed with the teeth before mentioned, denomi- iQated by Reaumur files (limes), and another pointed like ^ lancet, and not denticulated. The denticulated pieces, [%ioreover, are capable of being moved forwards and back- l^ards, while the centre one remains stationary ; and as ^this motion is eft'ected by pressing- a pin or the blade of '"^ knife over the muscles on either side at the origin of the ovipositor, it may be presumed that those muscles are destined for producing similar movements when the insect requires them. By means of a finely pointed pin carefully introduced between the pieces, and pushed very gently downwards, they may be, with no great difficulty, separated in their whole extent. whiCI^^ contrivance by which those three pieces are held tumo'^> while at the same time the two files can be easily 'pin motion, is similar to some of our own mechanical (.^^'ventions, with this difference, that no human workman «ould construct an instrument of this description so small, fine, exquisitely polished, and fitting so exactly. We should have been apt to form the grooves in the central piece, whereas they are scooped out in the handles of the files, and play upon two projecting ridges in the central piece, by which means this is rendered stronger. M. Reaumur discovered that the best manner of showing the play of this extraordinary instrument is to cut it oft' with a 'pair of scissors near its origin, and then, taking it between the thumb and the finger at the point of section, •work it gently to put the files in motion. Beside the muscles necessary for the movement of the files, the handle of each is terminated by a curve of the .same hard horny substance as itself, which not only fur- nishes the muscles with a sort of lever, but serves to press, TKEE-HOrrERS. 145 Ovipositors, with files, of Tree-hopper, magnified. as with a spring, the two files close to the central piece, as is shown in the lower figure. « M. Pontedera, who studied the economy of the tree- hoppers with some care, was anxious to see the insect itself make use of the ovipositor in forming grooves in wood, but found that it was so shy and easily alarmed, that it took to flight whenever he approached ; a circum- stance of which Reaumur takes advantage, to soothe his regret that the insects were not indigeno\is in his neigh- bourhood. But of their workmanship, when completed, he had several specimens sent to him from Provence and Languedoc by the Marquis de Caumont. The gall-flics, when about to deposit their eggs, select growing plants and trees ; but the tree-hoppers, on the contrary, make choice of dead, dried branches, for the mother seems to be aware that moisture would injure her progeny. The branch, commonly a small one, in which eggs have been deposited, may be recognised by being 146 INSECT ARCHITECTURE. covered with little oblong elevations caused by small splinters of the wood, detached at one end, but left fixed at the other by the insect. These elevations are for the most part in a line, rarely in a double line, nearly at equal distances from each other, and form a lid to a cavity in the wood, about four lines in length, containing Excavations for eg^s of Tree-hopper, with tlie chip-lids raised. from four to ten eggs. It is to be remarked, that the insect always selects a branch of such dimensions, that it can get at the pith, not because the pith is more easily bored, for it does not penetrate into it at all, but to form a warm and safe bed for the eggs. M. Pontedera says, that when the eggs have been deposited, the insect closes the mouth of the hole with a gum capable of protecting them from the weather; but M. Reaumur thinks this only a fancy, as, out of a great number which he exa- mined, he could discover nothing of the kind. Neither is such a protection wanted ; for the woody splinters above mentioned furnish a very good covering. The grubs hatched from these eggs (of which, M. Pon- tedera says, one female will deposit from five to seven hundred) issue from the same holes through which the eggs have been introduced, and betake themselves to the ground to feed on the roots of plants. They are not transformed into chrysalides, but into active nymphs, remarkable for their fore limbs, which are thick, strong, and furnished with prongs for digging ; and when we are told, by Dr. Le Fevre, that they make their way easily into hard stiif clay, to the depth of two or three feet, we perceive how necessary to them such a conformation must be. saw-flies. 147 Saw-Flies. An instrument for cutting grooves in wood, still more ingeniously contrived than that of the tree-hopper, was first observed by Vallisnieri, an eminent Italian naturalist, in a four-winged fly, most appropriately denominated by M. Reaumur the saw-Jly {Tenthredo) , of which many sorts are indigenous to Great Britain. The grubs from which those flies originate are indeed but too well known, as they frequently strip our rose, gooseberry, raspberry, and red currant trees of their leaves, and are no less de- structive to birch, alder, and willows ; while turnips and wheat suffer still more seriously by their ravages. These grubs may readily be distinguished from the caterpillars of moths and butterflies by having from sixteen to twenty- eight feet, by which they usually hang to the leaf they feed on, while they coil up the hinder part of their body in a spiral ring. The perfect flies are distinguished by four transparent wings ; and some of the most common have a flat body of a yellow^ or orange colour, while the head and shoulders are black. In order to see the ovipositor, to which we shall for the present turn our chief attention, a female saw-fly must be taken, and her belly gently pressed, when a narrow slit will be observed to open at some distance from the apex, and a short, pointed, and somewhat curved body, of a brown colour and horny substance, will be protruded. The curved plates which form the sides of the slit, are the termination of the sheath, in which the instrument lies concealed till it is wanted by the insect The appear- ance of this instrument, however, and its singular struc- ture, cannot be well understood without the aid of a microscope. The instrument thus brought into view is a very finely contrived saw, made of a horny substance, and adapted for penetrating branches and otlier parts of plants where the eggs are to be deposited. The ovipositor-saw of the insect is much more complicated than any of those em- ployed by our carpenters. The teeth of our saws are formed in a line, but in such a manner as to cut in two 148 IXSECT ARCHITECTURE. a, Ovipositor of Saw-fly, protiuded from its sheath, magnified. lines parallel to, and at a small distance from, each other. This is effected by slightly bending the points ot" the alternate teeth right and left, so that one halfof the whole teeth stand a little to the right, and the other half a little to the left. The distance of the two parallel lines thus formed is called the course of the saw, and it is only the portion of wood which lies in the course that is cut into saw-dust by the action of the instrument. It will follow, that in proportion to the thinness of a saw there will be the less destruction of wood which may be sawed. When cabinet-makers have to divide valuable wood into very thin leaves, they accordingly employ saws with a narrow course ; while sawyers who cut planks, use one with a broad course. The ovipositor-saw being extremely fine, does not require the teeth to diverge much, but fiom the manner in which they operate, it is requisite that they should not stand, like those of our saws, in a straight line. The greater portion of the edge of the instrument, on the contrary, is towards the point somewhat concave, similar to a scythe, while towards the base it becomes a little convex, the whole edge being nearly the shape of an Italic/. The ovipositor-saw of the fly is put in motion in the same way as a carpenter's hand-saw, supposing the tendons attached to its base to form the handle, and the muscles which put it in motion to be the hand of the carpenter. SAW-FLIES. 149 Ovipositor-saw of Saw-fly, with rasps shown in tlie cross lines. Bat the carpenter can only work one saw at a time, whereas each of these flies is furnished with two, equal and similar, which it works at the same time — one being advanced and the other retracted alternately. The secret, indeed, of working more saws than one at once is not un- known to our mechanics ; for two or three are sometimes fixed in the same frame. These, however, not only all move upwards and downwards simultaneously, but cut the wood in different places ; while the two saws of the ovi- positor work in the same cut, and consequently, though the teeth are extremely fine, the effect is similar to a saw with a wide set. It is important, seeing that the ovipositor-saws are so fine, that they be not bent or separated while in opera- tion — and this, also, nature has provided for, by lodging the backs of the saws in a groove, formed by two mem- braneous plates, similar to the structure of a clasp-knife. These plates are thickest at the base, becoming gradually thinner as they approach the point which the form of the saws requires. According to Yallisnieri, it is not the 150 INSECT ARCHITECTURE. only use of this apparatus to form a back for the saws, he having discovered, between the component membranes, two canals, which he supposes are employed to conduct the eggs of the insect into the grooves which it has hol- lowed out for them.* The teeth of a carpenter's saw, it may be remarked, are simple, whereas the teeth of the ovipositor-saw are themselves denticulated with fine teeth. The latter, also, combines at the same time the properties of a saw and of a rasp or file. So far as we are aware, these two proper- ties have never been combined in any of the tools of our carpenters. The rasping part of the ovipositor, however, is not constructed like our rasps, with short teeth thickly studded together, but has teeth almost as long as those of the saw, and placed contiguous to them on the back of the instrument, resembling in their form and setting the teeth of a comb, as may be seen in the figure. Of course, such observations are conducted with the aid of a mi- croscope. Portion of Saw-fly's comb-toothed rasp, and saw. When a female saw-fly has selected the branch of a rose-tree, or any other, in which to deposit her eggs, she may be seen bending the end of her belly inwards, in form of a crescent, and protruding her saw, at the same time, to penetrate the bark or wood. She maintains this recurved position so long as she works in deepening the groove ; but when she has attained the depth required, she unbends her body into a straight line, and in this position works upon the place lengthways, by applying the saw more horizontally. When she has rendered the * Reaumur, Mem. des Insectes, v, p. 3. saw-flip:s. 151 groove as large as she wishes, the motion of the tendons ceases, and an egg is placed in the cavity. The saw is then withdrawn into the sheath for about two-thirds of its length, and at the same moment a sort of frothy liquid, similar to a lather made with soap, is dropped over the egg, either for the purpose of gluing it in its place or sheathing it from the action of the juices of the tree. She proceeds in the same manner in sawing out a second groove, and so on in succession till she has deposited all her eggs, sometimes to the number of twenty- four. The grooves are usually placed in a line, at a small distance from one another, on the same branch ; but sometimes the mother fly shifts to another, or to a different part of the branch, when she is either scared or finds it unsuit- able. She commonly, also, takes more than one day to the work, notwithstanding the superiority of her tools. Reaumur has seen a saw-fly make six grooves in succes- sion, which occupied her about ten hours and a half. The grooves, when finished, have externally little elevation above the level of the bark, appearing like the puncture of a lancet in the human skin ; but in the course of a day or two the part becomes first brown and then black, while it also becomes more and more elevated. This increased elevation is not owing to the growth of the bark, the fibres of which, indeed, have been destroyed by the ovipositor-saAv, but to the actual growth of the egg ; for when a new-laid egg of the saw-fly is compared with one which has been several days enclosed in the groove, the latter will be found to be very considerably the larger. This growth of the egg is contrary to the analogy observable in the eggs of birds, and even of most other insects ; but it has its advantages. As it continues to increase, it raises the bark more and more, and conse- quently widens, at the same time, the slit at the entrance ; so that, when the grub is hatched, it finds a passage ready for its exit. The mother fly seems to be aware of this growth of her eggs, for she takes care to deposit them at such distances as may prevent their disturbing one another by their development. Another species of saw-fly, with a yellow body and 152 IKSECT ARCHITECTURE. deep violet-coloured wings, which also selects the rose- tree, deposits her eggs in a different manner. Instead of making a groove for each egg, like the preceding, she forms a large single groove, sufficient for about two dozen eggs. These eggs are all arranged in pairs, forming two straight lines parallel to the sides of the branch. The eggs, however, though thus deposited in a common groove, are carefully kept each in its place ; for a ridge of the wood is left to prevent those on the right from touching those on the left — and not only so, but between each egg of a row a thin partition of wood is left, forming a shallow cell. Nest of eggs of Saw-fly, iu rose tree. The edges of this groove, it will be obvious, must be farther apart than those which only contain a single egg, and, in fact, the whole is open to inspection ; but the eggs are kept from falling out, both by the frothy glue before mentioned and by the walls of the cells containing them. They were observed also, by Vallisnieri, to increase in size like the preceding. ( 1^3 ) CHAPTER VIII. Leaf-rolling Caterpillars. The labours of those insect-architects, which we have endeavoured to describe in the preceding pages, have been chiefly tliose of mothers to form a secure nest for their eggs, and the young hatched from them, during the first stage of their existence. But a much more numerous and not less ingenious class of architects may be found among the newly hatched insects themselves, who, un- taught by experience, and altogether unassisted by pre- vious example, manifest the most marvellous skill in the construction of tents, houses, galleries, covert-ways, forti- fications, and even cities, not to speak of subterranean caverns and subaqueous apartments, which no human art could rival. The caterpillars, which are familiarly termed leaf- rollers, are perfect hermits. Each lives in a cell, which it begins to construct almost immediately after it is hatched ; and the little structure is at once a house which protects the caterpillar from its enemies, and a store of ibod for its subsistence, while it remains shut up in its prison. But the insect only devours the inner folds. The art which these cater])illars exercise, although called into action but once, perhaps, in their lives, is perfect. They accomplish their purpose with a mechanical skill, which is remarkable for its simplicity and unerring success. The art of rolling leaves into a secure and immoveable cell may not appear very difficidt : nor would it be so if the caterpillars had fingers, or any parts which were equivalent to those delicate and admirable natural instruments with which man accomplishes his most ela- borate works. And yet the human fingers could not roll VOL. I. H 154 IJS'SECT ARCHITECTURE. a rocket-case of j)aper more regularly than the caterpillar rolls his house of leaves. A leaf is not a very easy sub- stance to roll. In some trees it is very brittle. It has also a natural elasticity, — a disposition to sj)ring back if it be bent, — which is caused by the continuity of its threads, or nervures. This elasticity is s})eedily over- come by the ingenuity with which the caterpillar works ; and the leaf is thus retained in its artificial position for many weeks, under every variety of temperature. We will examine, in detail, how these little leaf-rollers accom- ■^)lish their task. One of the most common as well as the most simple fabrics constructed by caterpillars, may be discovered during summer on almost every kind of bush and tree. We shall take as examples those which are found on the lilac, and on the oak. A small but very pretty chocolate-coloured rnoth, Lilac-tree Muth. (^Luxotcenia Riheana, Stephens ?) abundant in every garden, but not readily seen, from its frequently alighting on the ground, which is so nearly of its own colour, deposits its eggs on the leaves of the currant, the lilac, and of some other trees, appropriating a leaf to each egg. As soon as the caterpillar is hatched, :it begins to secure itself from birds and predatory insects by rolling up the lilac leaf into the form of a gallery, 'where it may feed in safety. We have repeatedly seen •one of them when just escaped from the egg, and only a few lines long, fix several silk threads from one edge of a leaf to the other, or from the edge to t,he mid-rib. Then going to the middle of the space, he shortened the threads by bending them with his feet, and consequently pulled the edges of the leaves into a circular form ; and he retained them in that position by gluing down each CATERPILLARS. Nest of ;i Lilac-leaf Roller. thread as he shortened it. In their younger state, those caterpillars seldom roll more than a small portion of the Another nest of Lilac leaf Roller. n2 1 56 INSECT ARCHITECTURE. leaf; but, when farther advanced, they unite the two edges together in their whole extent, with tiie exception of a small opening at one end, by which an exit may be made in case of need. Another species of caterpillar, closely allied to this, rolls up the lilac leaves in a different form, beginning at the end of a leaf, and fixing and pulling its threads till it gets it nearly into the shape of a scroll of parchment. To retain this form more securely, it is not contented, like the former insect, with threads fixed on the inside of the leaf; but has also recourse to a few cables which it weaves on the outside. Another species of moth, allied to the two preceding, is of a pretty green colour, and lays its eggs upon the Small green Oak-moth. {Tortrix Firidanc,.') leaves of the oak. This caterpillar folds them up in a similar manner, but with this difference, that it works on the under surface of the leaf, pulling the edge downwards and backwards, instead of forwards and upwards. This species is very abundant, and may readily be found as soon as the leaves expand. In June, when the perfect insect has appeared, by boating a branch of an oak, a whole shower of these pretty green moths may be shook into the air. Among the leaf-rolling caterpillars, there is a small dark-brown one, with a black head and six feet, very common in gardens, on the currant-bush, or the leaves of the rose-tree {Lozotcsjiia Bosatw, Stephe>'s). It is exceedingly destructive to the flower-buds. The eggs are deposited in the summer, and probably also in the autumn or in spring, in little oval or circular patches of a green colour. The grub makes its appearance with the first opening of the leaves, of whose structure in the CATERPLTiLAKS. 157 Nests of Oak-leaf- roiliug Caterpillars. half-expanded state it takes advantage to construct its summer tent. It is not, like some of the other leaf-rollers, contented with a single leaf, but weaves together as manj as there are in the bud where it may chance to have been hatched, binding their discs so firmly with silk, that all the force of the ascending sap, and the increasing growth of the leaves cannot break through ; a farther expansion is of course prevented. The little inhabitant in the mean- while banquets securely on the partitions of its tent, eating door-ways, from one apartment into another, through which it can escape in case of danger or dis- turbance. The leafits of the rose, it may be remarked, expand in nearly the same manner as a fan, and the operations of this ingenious little insect retain them in the form of a fan nearly shut. Sometimes, however, it is not contented ]58 lySECT ARCHITECTURE. with one bundle of leafits, but by means of its silken cords unites all m hich spring from the same bud into a rain-proof canopy, under the protection of which it can feast on the flower-bud, and prevent it from ever blowing. In the instance of the currant leaves, the proceedings of the grub are the same ; but it cannot unite the plaits so smoothly as in the case of the rose leafits, and it re- quires more labour also, as the nervures, being stiff, demand a greater effort to bend them. When all the exertions of the insect prove unavailing in its endeavours to draw the edges of a leaf together, it bends them in- wards as far as it can, and weaves a close web of silk over the open space between. This is well exemplified in one of the commonest of our leaf-rolling caterpillars, which may be found as early as February on the leaves of the nettle and the white archangel (Lamiiim album). It is of a light dirty-green colour, spotted with black, and covered ^vith a few hairs. In its young state it confines itself to the bosom of a small leaf, near the insertion of the leaf-stalk, partly bending the edges inwards, and covering in the interval with a silken curtain. As this sort of covering is not sufficient for concealment when the animal advances in growth, it abandons the base of the leaf for the middle, w:here it doubles up one side in a very secure and ingenious manner. Nest of the iscttle-leaf-rolling Caterpillar. We have watched this little architect begin and finish his tent upon a nettle in our study, the whole operation taking more than half an hour. (J. R.) lie began by walking over the plant in all directions, examining the CATERPILLARS. 159 loaves severally, as if to ascertain which was best fitted for his purpose by being pliable, and bending with thevveiglit of his body. Ilaving found one to his mind, he placed himself along the mid-rib, to the edge of which he secured himself firmly with the pro-legs of his tail ; then stretching his head to the edge of the leaf, he fixed a series of parallel cables between it and the mid-rib, with another series crossing these at an acute angle. The position in which he worked was most remarkable, for he did not, as might have been supposed, spin his cables with his face to the leaf, but throwing himself on his back, which was turned towards the leaf, he hung witii his whole weight by his first-made cables. This, by drawing them into the form of a curve, shortened them, and consequently pulled the edge of the leaf dowi> towards the mid-rib. The weight of his body was not, however, the only power which he employed ; for, using- the terminal pro-legs as a point of support, he exerted the whole muscles of his body to shorten his threads, and pull down the edge of the leaf. When he had drawn the threads as tight as he could, he held them till he spun fresh ones of sulficient strength to retain the leaf in the bent position into which he had pulled it. He then left the first series to hang loose while he shortened the fresh spun ones as before. This process was con- tmued till he had worked down about an inch and a half of the leaf, as much as he deemed sufficient for his habi- tation. This was the first part of the architecture. By the time he had worked to the end of the fold he had brought the edge of the leaf to touch the mid-rib ; but it was only held in this position by a few^ of the last spun threads, for all the first spun ones hung loose within. Apparently aware of this, the insect protruded more than half of its body through the small aperture left at the end, and spun several bundles of threads on the outside pre- cisely similar to those ropes of a tent which extend beyond the canvas, and are pegged into the ground. Unwilling to tnist the exposure of his whole body on the outside, lest he should be seized by the first sand- wasp (^od}jnents) or sparrow which might descry him, he now withdrew to complete the internal portion of his 160 INSECT ARCHITECTURE. dwelling, where the threads were hanging loose and disorderly. For this purpose he turned his head about, and proceeded precisely as he had done at the beginning of his task, but taking care to spin his new^ threads so as to leave the loose ones on the outside, and make his apartment smooth and neat. When he again reached the opposite end, he constructed there also a similar series of cables on the outside, and then withdrew to give some final touches to the interior. It is said by Kirby and Spence,* that when these leaf- rolling insects find that the larger nervures of the leaves are so strong as to prevent them from bending, they " weaken it by gnawing it here and there half through." We have never observed the circumstance, though we have witnessed the process in some hundreds of instances ; and we doubt the statement, from the careful survey w^iich the insect makes of the capabilities of the leaf before the operation is begun. If slie found upon examination that a leaf would not bend, she would reject it, as we have often seen happen, and pass to another. (J. R.) A species of leaf-roller, of the most diminutive size, merits particular mention, although it is not remarkable in colour or figure. It is without hair, of a greenish white, and has all the vivacity of the other leaf-rollers. Sorrel is the plant on which it feeds ; and the manner in which it rolls a portion of the leaf is very ingenious. The structure w hich it contrives is a sort of conical pyramid, composed of five or six folds lapped round each other. From the position of this little cone the cater- pillar has other labours to perform, beside that of rolling the leaf. It first cuts across the leaf, its teeth acting as a pair of scissors ; but it does not entirely detach this seg- ment. It rolls it up very gradually, by attaching threads of silk to the plane surface of the leaf, as we have before seen ; and then, having cut in a different direction, sets the cone upright, by \^'eaving other threads, attached to the centre of the roll and the plane of the leaf, upon which it throws the weight of its body. This, it will be readily * Introfl. vol. i. p. 457. CATERPILLARS. 161 seen, is a somewhat complicated effort of mechanical skill. It has been minutely described by M. Reaumur ; but the following representation will perhaps make the process clearer than a more detailed account. Leaf-rolling Caterpillars of the Sorrel. This caterpillar, like those of which we have already spoken, devours all the interior of the roller. It weaves, also, in the interior, a small and thin cocoon of white silk, the tissue of which is made compact and close. It is then transformed into a chrysalis. The caterpillars of two of our largest and handsomest butterflies, the painted lady (^Cynthia cardui, Stephens), and the admirable, or Alderman of the London fly-fanciers ( Vanessa atalanta') , are also leaf-rollers. The first selects the leaves of the great spear-thistle, and sometimes those of the stemless or star thistle, which might be supposed rather difficult to bend ; but the caterpillar is four times as large and strong as those which we have been hitherto describing. In some seasons it is plentiful ; in others it is rarely to be met with : but the admirable is seldom scarce in any part of the country ; and by examining the leaves of nettles which appear folded edge to edge, in July and August, the caterpillar may be readily found. h3 162 IXSKCT ARCHITECTURE. Nests of the Hesperia malvae, \^ ith Caterpillar, Clirysalis, aud Butterflies. Another butterfly {Hesperia malvce) is met with on dry banks where mallows grow, in May, or even earlier, and also in August, but is not indigenous. The cater- pillar, which is grey, with a black head, and four sulphur- coloured spots on the neck, fokls around it the leaves of the mallow, upon which it feeds. There is nothing, however, peculiarly different in its proceedings from those above described ; but the care with which it selects and rolls up one of the smaller leaves, when it is about to be transformed into a chrysalis, is worthy of remark ; it joins it, indeed, so completely round and round, that it has somewhat the resemblance of an &%%. Within this green cell it lies secure, till the time arrives when it is ready to burst its cerements, and trust to the quickness of its wings for protection against its enemies. CATERPILLARS. 163 Among the nests of caterpillars which roll up parcels of leaves, we know none so well contrived as those which are found upon willows and a species of osier. The long and naiTow leaves of these plants are naturally adapted to he adjusted parallel to each other ; for this is the direction which they have at the end of each stalk, when they are not entirely developed. One kind of small smooth cater- pillar {Tortn'x chlorana), with sixteen feet, the under Nest of Willow-leaf Roller. part of which is brown, and streaked with white, fastens these leaves together, and makes them up into parcels. There is nothing particularly striking in the mechanical 164 INSECT AKCHITECTUEE. manner in which it constructs them. It does precisely what we should do in a similar case : it winds a thread round those leaves which must be kept together, from a little above their termination to a very short distance from their extreme point ; and as it finds the leaves almost con- stantly lying near each other, it has little difficulty in bringing them together, as is shown in the cut, a. The prettiest of these parcels are those which are made upon a kind of osier, the borders of whose leaves some- times form columnar bundles before they are become developed. A section of these leaves has the appearance of filigree work (see Z>, p. 163). A caterpillar which feeds upon the willow, and whose singular attitudes have obtained for it the trivial name of Ziczac, also constructs for itself an arbour of the leaves, by drawing them together in an ingenious manner. M. Roesel* has given a tolerable representation of this nest, and of the caterpillar. The caterpillar is found in June ; and the moth {Notodonta ziczac) from May to July in the following year (see cut, p. 165). Beside those caterpillars which live solitary in the folds of a leaf, there are others which associate, employing their united powers to draw the leaves of the plants they feed upon into a covering for their common protection. Among these we may mention the caterpillar of a small butterfly, the plantain or Glanville fritillary (Melitea cinxid), which is very scarce in this country. Although a colony of these caterpillars is not numerous, seldom amounting to a hundred individuals, the place which they have selected is not hard to discover. Their abode may be seen in the meadow in form of a tuft ot herbage covered with a white web, which may readily be mistaken, at first view, for that of a spider, but closer in- spection soon corrects this notion. It is, in fact, a sort of common tent, in which the whole brood lives, eats, and undergoes the usual transformations. The shape of this tent, for the most part, approaches the pyramidal, though that depends much upon the natural growth of the herbage ^* Roesel, cl. ii., Pap. Nocturn., tab. xx. fig. 1, 2, 3, 4, 5, 6. CATERPILLARS. I6tt Zicz.ic Caterpiliar and Nest. which comj)oses it. The interior is divided into com- partments formed by the union of several small tents, as it were, to which others have been from time to time added according to the necessities of the community. When they have devoured all the leaves, or at least those which are m©st tender and succulent, they abandon their first camp, and construct another contiguous to it under a tuft of fresh leaves. Several of these encamp- ments may sometimes be seen within the distance of a foot or two, when they can find plantain {Plantago lanceolata) fit for their purpose ; but though they prefer this plant, they content themselves with grass if it is not to be pro- cured. iCyG IXSECT ARCHITECTURE. When Ihey are about to cast their skins, but particu- larly when they perceive the approach of winter, they construct a more durable apartment in the interior of their ])rincipal tent. The ordinary web is thin and scnii- transparent, permitting the leaves to be seen through it ; but their winter canvas, if we may call it so, is thick, strong, and quite opaque, forming a sort of circular hall Avithout any partition, where the whole community lie coiled up and huddled together. Early in spring they issue forth in search of fresh food, and again construct tents to protect them from cold and ]'ain, and from the mid-day sun. M. Reaumur found upon trial, that it was not only the caterpillars hatched from the eggs of the same mother which would unite in constructing the common tent ; for different broods, when put together, worked in the same .social and harmonious manner. We ourselves ascertained, during the present summer (1829), that this principle of sociality is not confined to the same species, nor even to the same genus. The experiment which we tried was to confine two broods of different species to the same branch by placing it in a glass of water to prevent their escape. The caterpillars which we experimented on were several broods of the brovrn-tail moth {Porthesia auriflud), and the lackey {^Clisiocampa nenstrici). These we found to work with as much industry and harmony in constructing the common tent as if they had been at liberty on their native trees ; and when the lackeys encountered the brown-tails they manifested no alarm nor uneasiness, but passed over the backs of one another as if they had made only a ])ortion of the branch. In none of their operations did they seem to be subject to any discipline, each indi- vidual appearing to work, in perfecting the structure, from individual instinct, in the same manner as was remarked by M. Huber, in the case of the hive-bees.* In making such experiments, it is obvious that the species of cater- pillars experimented with must feed upon the same sort of plant. (J. R.) * Scor/. 113. CATERPILLARS. 167 The design of the caterpillars in rolling up the leaves is not only to conceal themselves from birds and predatory insects, but also to protect themselves from the cuckoo- tlies, which lie in wait in every quarter to deposit their eggs in their bodies, that their progeny may devour them. Their mode of concealment, however, though it appear to be cunningly contrived and skilfully executed, is not always successful, their enemies often discovering their hiding-place. We happened to see a remarkable instance of this last summer (1828), in the case of one of the lilac caterpillars which had changed into a chrysalis within the closely folded leaf. A small ichneumon, aware, it should seem, of the very spot where the chrysalis lay within the leaf, was seen boring through it with her ovipositor, and introducing her eggs through the punctures thus made into the body of the dormant insect. We allowed her to lay all her eggs, about six in number, and then put the leaf under an inverted glass. In a few days the eggs of the cuckoo-fly were hatched, the grubs devoured the lilac chrysalis, and finally changed into pupae in a case of yellow silk, and into perfect insects like their parent. (J. R.) ( 168 ) CHAPTER IX. Insects forming Habitations of detached Leaves. The habitations of the insects which we have just described consist of growing leaves, bent, rolled, or pressed together, and fixed in their positions by silken threads. But there are other habitations of a similar kind which are constructed by cutting out and detaching a whole leaf, or a portion of a leaf. We have already seen how dexterously the upholsterer-bees cut out small parts of leaves and petals with their mandibles, and fit them into their cells. Some of the caterpillars do not exhibit quite so much neatness and elegance as the leaf- cutting bees, though their structures answer all the pur poses intended ; but there are others, as we shall pre sently see, that far excel the bees, at least, in the delicate minutioe of their workmanship. We shall first advert to those structures which are the most simple.^ Not far from Longchamps, in a road through the Bois de Boulogne, is a large marsh, which M. Reaumur never observed to be in a dry state even during summer. This marsh is surrounded with very lofty oaks, and abounds with pondweed, the water ]>lant named by botanists pola77iogeton. The shining leaves of this plant, which are as large as those of the laurel or orange-tree, but thicker and more fleshy, are spread upon the surface of the water. Having pulled up several of these about the middle of June, M. Reaumur observed, beneath one of the first which he examined, an elevation of an oval shape, which was formed out of a leaf of the same plant. He carefully examined it, and discovered that threads of silk were attached to this elevation. Breaking the threads, he raised up one of the ends, and saw a cavity, in which POKDWEED TENT-MAKEH. 169 a caterpillar (^Hydrocajnpa Potamogetd) was lodged. An indefatigable observer, such as M. Reaumur, would na- turally follow up this discovery ; and he has accordingly given us a memoir of the pond weed tent-maker, distin- guished by his usual minute accuracy. In order to make a new habitation, the caterpillar fastens itself on the under side of a leaf of the Pota- mogetcn. With its mandibles it pierces some part of this leaf, and afterwards gradually gnaws a curved line, marking the form of the piece which it wishes to detach. When the caterpillar has cut off, as from a piece of cloth, a patch of leaf of the size and shape suited to its purpose, it is provided with half of the materials requisite for making a tent. It takes hold of this piece by its man- dibles, and conveys it to the situation on the under side of its own or another leaf, whichever is found most appro- priate. It is there disposed in such a manner that the under part of the patch — the side which was the under part of the entire leaf — is turned towards the under part of the new leaf, so that the inner walls of the cell or tent are always made by the under part of tvv'o portions of leaf. The leaves of the potamogeton are a little concave on the under side ; and thus the caterpillar produces a hollow cell, though the rims are united. The caterpillar secures the leaf in its position by threads of white silk. It then weaves in the cavity a cocoon, which is somewhat thin, but of very close tissue. There it shuts itself up, to appear again only in the form of the perfect insect, and is soon transformed into a chrysalis. In this cocoon of silk no point touches the water ; whilst the tent of leaves, lined with silk, has been constructed underneath the wat€r. This fact proves that the cater- pillar has a particular art by which it repels the water from between the leaves. When the caterpillar, which has thus conveyed and disposed a patch of leaf against another leaf, is not ready to be transformed into a chrysalis, it applies itself to make a tent or habitation which it may carry everywhere about with it. It begins by slightly fixing the piece against the perfect leaf, leaving intervals all round, between the 170 INSECT ARCHITECTURE. piece and leaf, at which it may project its head. The piece which it has fixed serves as a model for cutting out a similar piece in the other leaf. The caterpillar puts them accurately together, except at one end of the oval, where an opening is left for the insect to project its head through. When the caterpillar is inclined to change its situation, it draws itself forward by means of its scaly limbs, riveted upon the leaf. The membranous limbs, which are riveted against the inner sides of the tent, oblige it to follow the anterior part of 4^he body, as it advances. The caterpillar, also, puts its head out of the tent every time it desires to eat. There is found on the common chickweed {SteUaria 7ne{Ua), towards the end of July, a middle-sized smooth green caterpillar, having three brown spots bordered with white on the back, and six legs and ten pro-legs, whose architecture is worthy of observation. When it is about to go into chrysalis, towards the beginning of August, it gnaws off, one by one, a number of the leaves and smaller twigs of the chick-weed, and adjusts them into an oval cocoon, somewhat rough and unfinished externally, but smooth, uniform, and finely tapestried with white silk within. Here it undergoes its transformations securely, and, when the period of its pupa trance has expired in the following July, it makes its exit in the form of a yellowish moth, with several brown spots above, and a brown band on each of its four wings below. It is al?o furnished with a sort of tail. On the cypress spurge {Euphorbia cyparmias), a na- tive woodland plant, but not of very common occurrence, may be found, towards the end of October, a caterpillar of a middle size, sparely tufted with hair, and striped with black, white, red, and brown. The leaves of the plant, which are in the form of short narrow blades of grass, are made choice of by the caterpillar to construct its cocoon, which it does with great neatness and regularity, the end of each leaf, after it has been detached from the plant, being fixed to the stem, and the other leaves placed parallel, as they are successively added. The other ends of all these are bent inwards, so as to form a uniformly CYPRESS-SPURGE CATERPILLAR. 171 rounded oblong figure, somewhat larger at one end than at the other. Cypress-Spurge Caterpillar— (^c/on^cM Euphras^iep ?)—Xrith a Cocoon, on a l)ranch. A caterpillar which builds a very similar cocoon to the last-mentioned may be found upon a more common plant — the yellow snap-dragon or toad-flax (^Antirrhinum linaria) — which is to be seen in almost every hedge. It is somewhat shaped like a leech, is of a middle size, and the prevailing colour pearl-grey, but striped with yellow and black. It spins up about the beginning of September, forming the outer coating of pieces of de- tached leaves of the plant, and sometimes of whole leaves placed longitudinally, the whole disposed with great symmetry and neatness. The moth appears in the following June. It is worthy of remark, as one of the most striking instances of instinctive foresight, that the caterpillars which build structures of this substantial description are destined to lie much longer in their chrysalis trance than those which spin merely a flimsy web of silk. For the most part, indeed, the latter undergo their final trans- formation in a few weeks ; while the former continue en- tranced the larger portion of a year, appearing in the per- fect state the summer after their architectural labours have been completed. (J.R.) This is a remarkable example of 172 INSECT AKCHITECTUKE. the instinct which leads these little creatures to act as if under the dictates of prudence, and with a perfect know- ledge of the time, be it long or short, which will elapse before the last change of the pupa takes place. That the caterpillar, while weaving its cocoon and preparing to assume the pupa state, exercises any reflective faculties, or is aware of what is about to occur relative to its own self, we cannot admit. It enters upon a work of which it has had no previous experience, and which is per- formed, as far as contingencies allow, in the same manner by every caterpillar of the same species. Its labours, its mode of carrying them on, and the very time in which they are to be commenced, is all pre-appointed ; and an instinctive impulse urges and guides ; and with this instinct its organic endowments are in precise harmony ; nor does instinct ever impel to labours for which an animal is not provided. " The same wisdom," says Bonnet, " which has constructed and arranged with so much art the various organs of animals, and has made them concur towards one determined end, has also pro- vided that the different operations which are the natural results of the economy of the animal should concur to- wards the same end. The creature is directed towards his object by an invisible hand ; he executes with pre- cision, and by one eflbrt, those works which wc so much admire ; he appears to act as if he reasoned, to return to his labour at the proper time, to change his scheme in case of need. But in all this he only obeys the secret influence which drives him on. He is but an instrument which cannot judge of each action, but is wound up by that adorable Intelligence, which has traced out for every insect its proper labours, as he has traced the orbit of each planet. When, therefore, I see an insect working at the construction of a nest, or a cocoon, I am impressed with respect, because it seems to me that I am at a spectacle where the Supreme Artist is hid behind the curtain." * There is a small sort of caterpillar which may be found * Contemplation de la Nature, part xv. chap. 38. MOSS-BUILDL!SrG CATERPILLAR. 173 on old walls, feeding upon minute mosses and lichens, the proceedings of which are well v.orthy of attention. They are similar, in appearance and size, to the cater- pillar of the small cabbage-butterfly {Pontia I'cipcB)^ and are smooth and bluish. The material which they use in building their cocoons is composed of the leaves and branchlets of green moss, which they cut into suitable pieces, detaching at the same time along with them a portion of the earth in which they grow. They arrange these upon the walls of their building, with the moss on the outside, and the earth on the inside, making a sort of vault of the tiny bits of green moss turf, dug from the surface of the wall. So neatly, also, are the several pieces joined, that the whole might well be supposed to be a patch of moss which had grown in form of an oval tuft, a little more elevated than the rest growing on the wall. When these caterpillars are shut up in a box with some moss, without earth, they construct with it cells in form of a hollow ball, very prettily plaited and interwoven. Moss-Ccll of small Caterpillar (Bryophlla'perla?) In May last (1829), we found on the walls of Green- wich Park a great number of caterpillars, whose manners bore some resemblance to those of the grub described by M. Reaumur. (J. R.) They were of middle size, with a dull orange stripe along the back ; the head and sides of the body black, and the belly greenish. Their abodes were constructed with ingenuity and care. A caterpillar of this sort appears to choose either a part where the mortal- contains a cavity, or it digs one suited to its design. Over the opening of the hollow in the mortar it builds 174 IXSECT ARCHITECTUKE. an arched wall, so as to form a chamber considerably larger than is usual with other architect caterpillars. It selects grains of mortar, brick, or lichen, fixing them, by means of silk, firmly into the structure. As some of these vaulted walls were from an inch to an inch and a half long, and about a third of an inch wide and deep, it may be well imagined that it would require no little industry and labour to complete the work. Yet it does not demand more than a few hours for the insect to raise it from the foundation. Like all other insect architects, this cater- pillar uses its own body for a measuring rule, and j^artly for a mould, or rather a block or centre to shape the walls by, curving itself round and round concentrically with the arch which it is building. We afterwards found one of these caterpillars, which had dug a cell in one of the softest of the bricks, cover- ing itself on the outside with an arched wall of brick-dust, cemented with silk. As this brick was of a bright red colour, we were thereby able to ascertain that there was not a particle of lichen employed in the structure. The neatness mentioned by Reaumur, as remarkable in his moss-building caterpillars, is equally observable in that which we have just described ; for, on looking at the surface of the wall, it would be impossible for a person unacquainted with these structures to detect where they were placed, as they are usually, on the outside, level with the adjoining brick-work ; and it is only when they are opened by the entomologist, that the little architect is perceived lying snug in his chamber. If a portion of the wall be thus broken down, the caterpillar immediately commences repairing the breach, by piecing in bits of mortar and fragments of lichen, till we can scarcely distinguish the new portion from the old. ( 1'^ ) CHAPTER X. Caddis-Worms and Carpenter-Caterpillars. There is a very interesting class of grubs which live under water, where they construct for themselves move- able tents of various materials as their habits direct them, or as the substances they require can be conveniently procured. Among the materials used by these singular grubs, well-known to fishermen by the name of caddis- worms, and to naturalists as the larvm of the four-Minged flies in the order Trichoptera of Kirby and Spence, we may mention sand, stones, shells^ wood, and leaves, which are skilfully joined and strongly cemented. One of these grubs* forms a pretty case of leaves glued together longi- tudinally, but leaving an aperture sufficiently large for the inhabitant to put out its head and shoulders when it Leaf Ni'st of Caddis- Woim. wishes to look about for food. Another employs pieces of reed cut into convenient lengths, or of grass, straw, wood, &c., carefully joining and cementing each piece to its fellow as the work proceeds ; and he frequently finishes Rt»ed Nest of Caddis- Worm. the whole by adding a broad piece longer than the rest 176 INSECT ARCHITECTURE. to shade his door-way over-head, so that he may not be seen from above. A more laborious structure is reared by the grub of a beautiful caddis-fly (Phrr/ganea), which weaves together a group of the leaves of aquatic plants into a roundish ball, and in the interior of this forms a cell for its abode. The following figure from Roesel will give a more precise notion of this structure than a lengthened description. Another of these aquatic architects makes choice of the tiny shells of young fresh-water mussels and snails (Planorbis), to form a moveable grotto ; and as these little shells are for the most part inhabited, he keeps the Shell Nests of Caddis-Wonns. poor animals close prisoners, and drags them without mercy along with him. These grotto-building grubs are CADDIS-WOEMS. 177 by no means uncommon in ponds ; and in chalk districts, such as the country about Woolwich and Gravesend, they are very abundant. One of the most surprising instances of their skill occurs in the structures of which small stones are the principal material. The problem is to make a tube about the width of the hollow of a wheat straw or a crow quill, and equally smooth and uniform. Now the materials being small stones full of angles and irre- gularities, the difficulty of performing this problem will appear to be considerable, if not insurmountable : yet the little architects, by patiently examining their stones and turning them round on every side, never fail to ac- complish their plans. This, however, is only part of Stone Nest of Caddis- Worm. "* the problem, which is complicated with another condi- tion, and which we have not found recorded by former observers, namely, that the under surface shall be flat and smooth, without any projecting angles which might im- pede its progress when dragged along the bottom of the rivulet where it resides. The selection of the stones, indeed, may be accounted for, from this species living in streams where, but for the weight of its house, it would to a certainty be swept away. For this purpose, it is probable that the grub makes choice of larger stones than it might otherwise want ; and therefore also it is that we frequently find a case composed of very small stones and sand, to which, when nearly finished, a large Sand Nest balanc( d with a Stone. stone is added by way of ballast. In other instances, when the materials are found to possess too great specific VOL. I. I 178 ijnsect architecture. gi-avity, a bit of light wood, or a hollow straw, is added to buoy up the case. Nest of Caddis Worm balanced with Straws. It is worthy of remark, that the cement, used in all these cases, is superior to pozzolana * in standing water, in which it is indissoluble. The grubs themselves are also admirably adapted for their mode of life, the por- tion of their bodies which is always enclosed in the case, being soft like a meal-worm, or garden caterpillar, while the head and shoulders, which are for the most part projected beyond the door-way in search of food, are firm, hard, and consequently less liable to injury than the protected portion, should it chance to be exposed. "\Ye have repeatedly tried experiments with the in- habitants of those aquatic tents, to ascertain their mode of building. We have deprived them of their little houses, and furnished them with materials for constructing new ones, watching their proceedings from their laying the first stone or shell of the structure. They work at the commencement in a very clumsy manner, attaching a great number of chips to whatever materials may be within their reach with loose threads of silk, and many of these they never use at all in their perfect building. They act, indeed, much like an unskilful workman try- ing his hand before committing himself upon an intended work of difficult execution. Their main intention is, however, to have abundance of materials within reach : for after their dwelling is fairly begun, they shut them- selves up in it, and do not again protrude more than half of their body to procure materials ; and even when they Lave dragged a stone, a shell, or a chip of reed within building reach, they have often to reject it as unfit. (J. R.) 1 * A cement prepared of volcanic earth, or lava. GOAT-iMOTil. 179 CAEPEKTER-CATEKPILLAKS. Insects, though sometimes actuated by an instinct apparently blind, unintelligent, or unknown to them- selves, manifest in other instances a remarkable adapta- tion of means to ends. We have it in our power to exemplify this in a striking manner by the proceedings of the caterpillar of a goat-moth (Cossus ligniperda) -which we kept till it underwent its final change. Caterpillar of Goat-Moth ia a Willow Tree. This caterpillar, \^hich abounds in Kent and many other parts of the island, feeds on the wood of willows, oaks, poplars, and other trees, in which it eats extensive galleries ; but it is not contented with the protection afforded by these galleries during the colder months of winter, before the arrival of which it scoops out a hollow in the tree, if it do not find one ready prepared, suffi- ciently large to contain its body in a bent or somewhat coiled-up position. On sawing off a portion of an old poplar in the winter of 1827, we found such a cell with a caterpillar coiled up in it. I 2 180 IXSECT AKCHITECTDRE. V inter Nest of the Goat- Caterpillar. It had not, however, been contented with the bare walls of the retreat which it had hewn out of the tree, Jbr it had lined it with a fabric as thick as coarse broad- cloth, and equally warm, composed of the raspings of the wood scooped out of the cell, united with the strong silk which every species of caterpillar can spin. In this snug retreat our caterpillar, if it had not been disturbed, would have spent the winter without eating ; but upon being removed into a warm room and placed under a glass along with some pieces of wood, which it might eat if so inclined, it was roused for a time from its dor- mant state, and began to move about. It was not long, however, in constructing a new cell for itself, no less ingenious than the former. It either could not gnaw into the fir plank, where it was now placed with a glass above it, or it did not choose to do so ; for it left it un- touched, and made it the basis of the edifice it began to construct. It formed, in fact, a covering for itself pre- cisely like the one from which we had dislodged it, — composed of raspings of wood detached for the purpose from what had been given it as food, — the largest piece of which was employed as a substantial covering and pro- tection for the whole. It remained in this retreat, mo- tionless, and without food, till revived by the warmth of the ensuing spring, when it gnawed its way out, and began to eat voraciously, to make up for its long fast, GOAT-MOTH. 181 These caterpillars are three years in arri\ ing at their final change into the winged state ; but as the one just mentioned was nearly full grown, it began, in the month of May, to prepare a cell, in which it might undergo its metamorphosis. Whether it had actually improved its skill in architecture by its previous experience we will not undertake to say, but its second cell was greatly superior to the first. In the first there was only one large piece of wood employed ; in the second, two pieces were placed in such a manner as to support each other, and beneath the angle thus formed an oblong structure was made, composed, as before, of wood-raspings and silk, but much stronger in texture than the winter cell. In a few weeks (four, if we recollect aright) the moth came forth. (J. R.) Nest of Goat-Motli. — Figured fiora specLmcu, and raised to show the Til pa. A wood-boring caterpillar, of a species of moth much rarer than the preceding (^^geria asiliformis, Stephexs), exhibits great ingenuity in constructing a cell for its me- tamorphosis. We observed above a dozen of them dur- ing this summer (1829) in the trunk of a poplar, one side of which had been stripped of its bark. It was this portion of the trunk which all the caterpillars selected for their final retreat, not one having been observed where the tree was covered with bark. The ingenuity of the little architect consisted in scooping its cell almost to the very surface of the wood, leaving only an exterior 182 INSECT AECHITECTURE. covering of unbroken' wood, as thin as writing paper. Previous, therefore, to the chrysalis making its way through this feeble barrier, it could not have been sus- pected that an insect was lodged under the smooth wood. We observed more than one of these in the act of break- ing through this covering, within which there is besides a round moveable lid of a sort of brown wax. (J. R.) Another architect caterpillar, frequently to be met with in July on the leaves of the willow and the poplar, is, in the fly-state, called the puss-moth ( Centra vinula). The caterpillar is produced from brown-coloured shining eggs, about the size of a pin's head, which are deposited — one, two, or more together — on the upper surface of a leaf. In the course of six or eight weeks (during which time it casts its skin thrice) it arrives at its full growth, when it is about as thick, and nearly as long, as a man's thumb, Eggs of the Puss Moth. and begins to prepare a structure in which the pupa may sleep securely during the winter. As we have, oftener than once, seen this little architect at work, from the foundation till the completion of its edifice, we are thereby enabled to give the details of the process. The puss, it may be remarked, does not depend for protection on the hole of a tree, or the shelter of an over- hanging branch, but upon the solidity and strength of the fabric which it rears. The material it commonly uses is the bark of the tree upon which the cell is constructed ; but when this cannot be procured, it is contented to em- ploy whatever analogous materials may be within reach. One which we had shut up in a box substituted the marble paper it was lined with for bark, which it could not pro- PUSS-MOTH. 183 cure.* With silk it first wove a thin web round the edges of the place which it marked out for its edifice ; then it ran several threads in a spare manner from side to side, and from end to end, but very irregularly in point of arrangement ; these were intended for the skeleton or frame-work of the building. When this outline was finished, the next step was to strengthen each thread of silk by adding several (sometimes six or eight) parallel ones, all of which were then glued together into a single thread, by the insect running its mandibles, charged with gluten, along the line. The meshes, or spaces, which were thus widened by the compression of tlie parallel threads, were immediately filled up with fresh threads, ' * It is justly remarked by Reaumur, that when caterpillars are left at liberty among their native plants, it is only by lucky chance they can be ol)served building their cocoons, because the greater number abandon the plants upon which they have bsen feeding, to spin tip in places at some distance. In order to see their operations the)' must be kept in confinement, par- ticularly in boxes with glazed doors, where they may be always under the eye of the naturalist. In such circumstances, how- ever, we may be ignorant what building materials we ought to provide them with for their structures. A red caterpillar, with a few tufts of hair, which Reaumur found in July feeding upon the flower bunches of the nettle, and refusing to touch the leaves, began in a few days to prepare its cocoon, by gnawing the paper lid of the box in which it was placed. This, of course, was a material which it could not have procured in the tields, but it was the nearest in properties that it could pro- cure ; for, thougli it liad the leaves and stems of nettles, it never used a single fragment of either. When Reaumur found that it was likely to gnaw through the paper lid of the box, and might effect its escape, he furnished it with bits of rumpled paper, fixed to the lid by means of a pin ; and these it chopped down into such pieces as it judged convenient for its structure, which it took a day to complete. The moth appeared four weeks after, of a brownish-black colour, mottled with white, or rather grey, in the manner of lace. Bonnet also mentions more than one instance in which he observed caterpillars making use of paper, when they could not procure other materials. 184 INSECT AKCHITECTUBE. ■Rudiments of the Cell of the Puss Motli. till at length only very small spaces were left. It was in this stage of the operation that the paper came into requi- sition, small portions of it being gnawed off the box and glued into the meshes. It was not, however, into the meshes only that the bits of paper were inserted ; for the whole fabric was in the end thickly studded over with them. In about half a day from the first thread of the frame-work being spun the building was completed. It was at first, however, rather soft, and yielded to slight pressure with the finger ; but as soon as it became tho- roughly dry, it was so hard that it could with difficulty be penetrated with the point of a penknife. (J. R.) Cell built by the Larva of the Puss-Moth. A question will here suggest itself to the curious in- quirer, how the moth, which is not, like the caterpillar, furnished with mandibles for gnawing, can find its way through so hard a wall. To resolve this question, it is asserted by recent naturalists (see Kirby and Spence, vol. iii. p. 15), that the moth is furnished with a peculiar acid for dissolving itself a passage. We have a specimen of the case of a puss-moth, in which, notwithstanding its strength, one of the ichneumons had contrived to deposit CAPRICOKK-BEETLE. 185 its esrgs. In the beginning of summer, when we expected the moth to appear, and felt anxious to observe the re- corded effects of the acid, we were astonished to find a large orange cuckoo-fily make its escape ; while another, which attempted to follow, stuck by the way and died. On detaching the cell from the box, we found several others, which had not been able to get out, and had died in their cocoons. (J. R.) Ichneumon (OpJiion luteum), figured from the one mrntioned. Among the carpenter-grubs may be mentioned that of the purple capricorn-beetle (CalUdium violaceum), of which the Rev. Mr. Kirby has given an interesting account in the fifth volume of the ' Linnaean Transactions.' This insect feeds principally on fir timber which has been felled some time without having had the bark stripped oft"; but it is often found on other wood. Though occa- sionally taken in this kingdom, it is supposed not to have been originally a native. The circumstance of this destructive little animal attacking only such timber as had not been stripped of its bark ought to be attended to by all persons who have any concern in this article ; for the bark is a temptation not only to this, but to various other insects ; and much of the injury done in timber might be prevented, if the trees were all barked as soon as they were felled. The female is furnished, at the posterior extremity of her body, with a flat retractile tube, which she inserts between the bark and the wood, to the depth of about a quarter of an inch, and there deposits a single agg. By stripping off the bark, it is easy to trace the whole progress of the grub, from the spot where it is hatched, to that where it attains its full size. It first proceeds in a serpentine direction, filling the space which it leaves with its excrement, resembling saw-dust, and so 1 3 186 INSECT ARCHITECTUKE. stopping all ingress to enemies from without. When it has arrived at its utmost dimensions, it does not confine itself to one direction, but works in a kind of labyrinth, eating backwards and forwards, which gives the wood under the bark a very irregular surface ; by this means its paths are rendered of considerable width. The bed of its paths exhibits, when closely examined, a curious appear- ance, occasioned by the gnavv ings of its jaws, which exca- vate an infinity of little ramified canals. "When the insect is about to assume its chrysalis state, it bores down ob- liquely into the solid wood, to tb.e depth sometimes of three inches, and seldom if ever less than two, forming holes nearly semi-cylindrical, and of exactly the form of tlie grub which inhabits them. At first sight one would wonder how so small and seemingly so weak an animal could have strength to excavate so deep a mine ; but when we examine its jaws our wonder ceases. These are large, thick, and solid sections of a cone divided longitudinally, which, in the act of chewing, ap})ly to each other the whole of their interior plane surface, so that they grind the insect's food like a pair of millstones. Som.e of the grubs are hatched in October ; and it is supposed that about the beginning of March they assume their chrysalis state. At the place in the bark opposite to the hole from whence they descended into the wood, the perfect insects gnaw their way out, which generally takes place betwixt the middle of May and the middle of June. These insects are supposed to fly only in the night, but during the day they may generally be found resting on the wood from which they were disclosed. The gi'ubs are destitute of feet, pale, folded, somewhat hairy, convex above, and divided into thirteen segments. Their head is large and convex.* 'i It would not be easy to find a more striking example of ingenuity than occurs in a small caterpillar which may be found in May, on the oak, and is supposed by Kirby and Spence to be that of the Pyralis strigulalis. It is of a whitish yellow colour, tinged with a shade of carnation, * Kirby, in ' Linn. Trcns ,' vol. v. p. 216, and Introd. ii. OAK-BARK CATEKPILLAR. 187 and studded with tufts of red hairs on each segment, and two brown spots behind the head. It has fourteen feet, and the upper part of its body is much flatter than is common in caterpillars. When this ingenious little insect begins to form its cell, it selects a smooth young branch of the oak, near an offgoing of the branchlets whose angle may afford it some protection. It then measures out, with its body for a rule, the space destined for its structure, the basement of which is of a triangular form, with the apex at the lower end. The building itself is composed of small rectangular strap-shaped pieces of the outer bark of the branch cut out from the immediate vicinity ; the insect indeed never travels farther for materials than the length of its own body. Upon the two longest sides of the tri- angular base it builds uniform walls, also of a triangular shape, and both gradually diverging from each other as they increase in height. These are formed with so much mathematical precision, that they fit exactly when they ^& Magnified Cells of Pyialis slrigulalis ? o. The walls before they are joined, h. Walls jcinpd, l;ut not clo?id at tr>p. c. Side view of structure coiaplete. 188 IKSECT AKCHITKCTUBE. are afterwards brought into contact. As soon as the little architect has completed these walls, which resemble very much the feathers of an arrow, it proceeds to draw them together in a manner similar to that which the leaf-rolling caterpillars employ in constructing their abodes, by pull- ing them with silken cords till they bend and converge. Even when the two longest sides are thus joined, there is an opening left at the upper end, which is united in a similar manner. When the whole is finished, it requires close insj)ection to distinguish it from the branch, being formed of the same materials, and having consequently the same colour and gloss. Concealment, indeed, may be supposed, with some justice, to be the final object of the insect in producing this appearance, the same principle being ex- tensively exemplified in numerous other instances. ( 189 ) CHAPTER XI. Earth-mason Caterpillars. Many species of caterpillars are not only skilful in con- cealing themselves in their cocoons, but also in the con- cealment of the cocoon itself; so that even when that is large, as in the instance of the death's-head hawk-moth (^Acherontia atropos), it is almost impossible to find it. We allude to the numerous class of caterpillars which, previous to their changing into the pupa state, bury them- selves in the earth. This circumstance would not be surprising, were it confined to those which are but too well known in gardens, from their feeding upon and de- stroying the roots of lettuce, chicory, and other plants, as they pass a considerable portion of their lives under ground ; nor is it surprising that those which retire under ground during the day, and come abroad to feed in the night, should form their cocoons where they have been in the habit of concealing themselves. But it is very singular and unexpected, that caterpillars which pass the whole of their life on plants and even on trees, should afterwards bury themselves in the earth. Yet, the fact is, that perhaps a greater number make their cocoons under than above ground, particularly those which are not clothed with hair. Some of those caterpillars, which go into the ground previous to their change, make no cocoon at all, but are contented with a rude masonry of earth as a nest for their pupae : into the details of their operations it will not be so necessary for us to go, as into those which exhibit more ingenuity and care. When one of the latter is dug up it has the appearance of nothing more than a small clod of earth, of a roundish or oblong shape, but, generally, by no means uniform. The interior, however, when it is laid 190 INSECT ARCHITECTURE. open, always exhibits a cavity, smooth, polished, and regular, in which the cocoon or the chrysalis lies secure (Fig. B, p. 191). The polish of the interior is precisely such as might be given to soft earth by moistening and kneading it with great care. But beside this, it is usually lined with a tapestry of silk, more or less thick, though this cannot always be discovered without the aid of a mag- nifying glass. This species of caterpillars, as soon as they have completed their growth, go into the earth, scoop out, as the cossus does in wood, a hollow cell of an oblong form, and line it with pellets of earth, from the size of a grain of sand to that of a pea — united, by silk or gluten, into a fabric more or less compact, according to the spe- cies, but all of them fitted for protecting the inhabitant, during its winter sleep, against cold and moisture. Outside vit'W of Ne&ts of EaitJi masou Caterpillars. One of the examples of this occurs in the ghost-moth {Hepialns hwmdi), which, before it retires into the earth, feeds upon the roots of the hop or the burdock. Like other insects which construct cells under ground, it lines the cemented earthen walls of its cell with a smooth tapestry of silk, as closely woven as the web of the house- spider. Inaccurate observers have inferred that these earthen structures were formed by a very rude and unskilful pro- cess — the caterpillar, according to them, doing nothing more than roll itself round, M'hile the mould adhered to the gluey perspiration with which they describe its body to be covered. This is a process as far from the truth as Aristotle's account of the spider spinning its web from wool taken from its body. Did the caterpillar do nothing EARTH-MASOX CATEP.PILL.ABS. 191 Nests, &c., of an Earth-maiou Caterpillar. more than roll itself in the earth, the cavity would be a long tube fitted exactly to its body {Jig. c) : it is essen- tially different. It does not indeed require very minute observation to perceive, that every grain of earth in the structure is united to the contiguous grains by threads of silk ; and that consequently, instead of the whole having been done at once, it must have required \Qry considerable time and labour. This construction is rendered more obvious by throwing one of these earthen cases into water, which dissolves the earth, but does not act on the silk which binds it together. To understand how tliis is performed, it may not be uninteresting to follow the little mason from the beginning of his task. When one of those burrowing caterpillars has done 192 IXSECT ARCHITECTUKE. feeding, it enters the earth to the depth of several inches, till it finds mould fit for its purpose. Having nowhere to throw the earth which it may dig out, the only means in its power of forming a cavity is to press it with its body ; and, by turning round and round for this purpose, an oblong hollow is soon made. But M'ere it left in this state, as Reaumur well remarks, though the vault might endure the requisite time by the viscosity of the earth alone, were no change to take place in its humidity, yet, as a great number are wanted to hold out for six, eight, and ten months, they require to be substantially built ; a mere lining of silk, therefore, would not be sufficient, and it becomes necessary to have the walls bound with silk to some thickness. When a caterpillar cannot find earth sufficiently moist to bear kneading into the requisite consistence, it has the means of moistening it with a fluid which it ejects for the purpose ; and as soon as it has thus prepared a small pellet of earth, it fits it into the wall of the vault, and secures it with silk. As the little mason, however, always works on the inside of the building, it does not, at first view, appear in what manner it can procure materials for making one or two additional walls on the inside of the one first built. As the process takes place under ground, it is not easy to discover the particulars, for the cater- pillars will not work in glazed bexes. The difficulty was completely overcome by M. Reaumur, in the instance of the caterpillar of the water-betony moth {Ciicullia scrophdo.ricB^ Schra>'k), which he permitted to construct the greater part of its underground building, and then dug it up and broke a portion off" from the end, leaving about a third part of the whole to be rebuilt. Those who are unacquainted with the instinct of insects might have suppcsed that, being disturbed by the demolition of its walls, it M'ould have left off work ; but the stimulus of providing for the great change is so powerful, that scarcely any disturbance will interrupt a caterpillar in this species of labour, The little builder accordingly was not long in recom- mencing its task for the purpose of repairing the disorder, EARXa-MASOA' CATERPILLABS. 193 Earth mason Caterpillar's Nests, with the perfect Moth, &C4 194 ' INSECT ARCHITECTURE. which it accomplished in about four hours. At first it pro- truded its body almost entirely beyond the breach which had been made, to reconnoitre the exterior for building ma- terials. Earth was put within its reach, of the same kind as it had previously used, and it was not long in selecting a grain adapted to its purpose, which it fitted into the wall and secured with silk. It first enlarged the outside of the wall by the larger and coarser grains, and then selected finer for the interior. But before it closed the ajjerture, it collected a quantity of earth on the inside, wove a pretty thick network tapestry of silk over the part vvhich remained open, and into the meshes of this, by pushing and pressing, it thrust grains of earth, securing them with silk till the whole was rendered opaque ; and the further operations of the insect could no longer be watched, except that it was observed to keep in motion, finishing, no doubt, the silken tapestry of the interior of its little chamber. When it was completed M. Reaumur ascertained that the portion of the structure which had been built under his eye was equally thick and compact with the other, which had been done under ground. The grubs of several of the numerous species of may- fly {Ephemera) excavate burrows for themselves in soft earth, on the banks of rivers and canals, under the level of the water, an operation well described by Scopoli, Sv/ammerdam, and Reaumur. The excavations are always proportioned to the size of the inhabitant ; and conse- quently, when it is young and small, the hole is propor- tionally small, though, with respect to extent, it is always at least double the length of its body. The hole, being under the level of the river, is always filled with water, so that the grub swims in its native element, and while it is secure from being preyed upon by fishes, it has its own food within easy reach. It feeds, in fact, if we may judge from its egesta, upon the slime or moistened clay with which its hole is lined. In the bank of the stream at Lee, in Kent, we had oc- casion to take up an old willow stump, which, previous to its being driven into the bank, had been perforated in numerous places by the caterpillar of the goat-moth EARTH-MA SOX CATERPILLARS. 195 Nests of tho Grubs of Ephemera. A, The Grub. B, Perforations in a river bnnk. C, One laid open to show the parallel structure. (Cossus ligniperdd) . From having been driven amongst the moist clay, these perforations became filled with it, and the grubs of the ephemerae found them very suitable for their habitation ; for the wood supplied a more secure protection than if their galleries had been excavated in the clay. In these holes of the wood we found several empty, and some in which were full-grown grubs. (J. R.) Nests of Epheraorfc in holes of Cossus. 196 LNSECT ARCHITECTURE. The architecture of the grub of a pretty genus of beetles, known to entomologists by the name of Cincin- dela, is peculiarly interesting. It was first made known by the eminent French naturalists, Geoftroy, Desmarest, and Latreille. This grub, which may be met with during spring, and also in summer and autumn, in sandy places, is long, cylindric, soft, whitish, and furnished with six brown scaly feet. The head is of a square form, with six or eight eyes, and very large in proportion to the body. They have strong jaws, and on the eighth joint of the body there are two fleshy tubercles, thickly clothed with reddish hairs, and armed with a recurved horny spine, the whole giving to the grub the form of the letter Z. With their jaws and feet they dig into the earth to the depth of eighteen inches, forming a cylindrical cavity of greater diameter than their body, and furnished with a perpendicular entrance. In constructing this, the grub first clears away the particles of earth and sand by placing them on its broad trapezoidal head, and carrying the load in this manner beyond the area of the excavation. When it gets deeper down, it climbs gradually up to the surface with similar loads by means of the tubercles on its back, above described. This process is a work of considerable time and difficulty, and in carrying its loads the insect has often to rest by the way to recover strength for a renewed exertion. Not unfrequently, it finds the soil so ill adapted to its operations, that it abandons the task altogether, and begins anew in another situation. When it has suc- ceeded in forming a complete den, it fixes itself at the entrance by the hooks of its tubercles, which are admir- ably adapted for the purpose, forming a fulcrum or sup- port, while the broad plate on the top of the head exactl}'- fits the aperture of the excavation, and is on a level with the soil. In this position the grub remains immoveable, with jaws expanded, and ready to seize and devour every insect which may wander within its reach, particularly the smaller beetles ; and its voracity is so great, that it does not spare even its own species. It precipitates its prey into the excavation, and in case of danger it retires to the bottom of its den, a circumstance which renders it TnE ANT-LIOy. 197 not a little difficult to discover the grub. The method adopted by the French naturalists was to introduce a straw or pliant twig into the hole, while they dug away, by degrees and with great care, the earth around it, and usually found the grub at the bottom of the cell, resting in a zig-zag position like one of the caterpillars of the geometric moths. When it is about to undergo its transformation into a pupa, it carefully closes the mouth of the den, and retires to the bottom in security. It does not appear that the grub of the genus Cincin- dela uses the excavation just described for the purpose of a trap or pitfall, any further than that it can more effec- tually secure its prey by tumbling them down into it ; but there are other species of grubs which construct pit- falls for the express purpose of traps. Among these is the larva of a fly {R/iagio vermileo), not unlike the com- mon flesh maggot. The den which it constructs is in the form of a funnel, the sides of which are composed of sand or loose earth. It forms this pitfall of considerable depth, by throwing out the earth obliquely on all sides ; and when its trap is finished, it stretches itself along the bot- tom, remaining stiff and motionless, like a piece of wood. The last segment of the body is bent at an angle with the rest, so as to form a strong point of support in the strug- gles which it must often have to encounter with vigorous prey. The instant that an insect tumbles into the pit- fall, the grub pounces upon it, writhes itself round it like a serpent, transfixes it with its jaws, and sucks its juices at its ease. Should the prey by any chance escape, the grub hurls up jets of sand and earth, with astonishing rapidity and force, and not unfrequently succeeds in again precipitating it to the bottom of its trap. The Akt-Liox. The observations of the continental naturalists have made known to us a pitfall constructed by an insect, the details of whose operations are exceedingly curious ; we refer to the grub of the ant-lion {Myrmeleon formicarius) , 1S8 INSECT AKCHITECTURE, which, though marked by Dr. Turton and Mr. Stewart as British, has not (at least of late years) been found in this country. As it is not, however, uncommon in France and Switzerland, it is probable it may yet be discovered in some spot hitherto unexplored, and if so, it will well reward the search of the cm'ious. The ant-lion grub being of a grey colour, and having its body composed of rings, is not unlike a wood-louse (Onisciis), though it is larger, more triangular, has only six legs, and most formidable jaws, in form of a reaping- hook, or a pair of calliper compasses. These jaws, how- ever, are not for masticating, but are perforated and tubular, for the purpose of sucking the juices of ants upon which it feeds. Vallisnieri was therefore mistaken, as Reaumur well remarks, when he supposed that he had discovered its mouth. Its habits require that it should walk backwards, and this is the only species of locomo- tion which it can perform. Even this sort of motion it executes very slowly ; and were it not for the ingenuity of its stratagems, it would fare but sparingly, since its chief food consists of ants, whose activity and swiftness of foot would otherwise render it impossible for it to make a single capture. Nature, however, in this, as in nearly every other case, has given a compensating power to the individual animal, to balance its privations. The ant-lion is slow, but it is extremely sagacious ; it cannot follow its prey, but it can entrap it. The snare which the grub of the ant-lion employs consists of a funnel-shaped excavation formed in loose sand, at the bottom of which it lies in wait for the ants that chance to stumble over the margin, and cannot, from the looseness of the walls, gain a sufficient footing to effect their escape. By shutting up one of these grubs in a box with loose sand, it has been repeatedly observed constructing its trap of various dimensions, from one to nearly three inches in diameter, according to circumstances. In the 'Magazine of Natural History,' 1838, p. 601, Mr. Westwood gives a very interesting account of the mode in which the ant-lion proceeds in the excavation of THE ANT-LION. 199 >r. Grub of the Aat-Lion, magnified, with one perfect Trap, and another beL'ua. its pitfall, as witnessed by himself in specimens procured in the Pare de Belle Vue, near Paris, where, at the foot of a very high sand-bank, these pits were numerous, and of various sizes, but none exceeded an inch and a half or two inches in diameter, and two-thirds of an inch deep. "The ant-lions were of various sizes, corresponding to the size of their retreats, I brought many of them to Paris, placing several together in a box filled with sand. They, however, destroyed one another whilst shut up in these boxes ; and I only succeeded in bringing three of them alive to England, one of v.hich almost immediately afterwards (on the 23d of July) enclosed itself in a glo- bular cocoon of fine sand. The other two afforded me many opportunities of observing their proceedings. They were unable to walk forwards, — an anomalous circum- stance, and not often met with in animals furnished with 200 INSECT ARCHITECTURE. well developed legs. It is generally backwards, working in a spiral direction, that the creature moves, pushing itself backwards and downwards at the same time, the head being carried horizontally, and the back much arched, so that the extremity of the body is forced into the sand. In this manner it proceeds backwards (to use an Hibernianism), forming little mole-hills in the sand. But it does not appear to me that this retrograde motion lias anything to do with the actual formation of the cell, since, as soon as it has fixed upon a spot for its retreat, it commences throwing up the sand wilh the back of its head, jerking the sand either behind its back or on one or the other side. It shuts its long jaws, forming them into a kind of shovel, the sharp edges of which it thrusts laterally into the sand on each side of its head, and thereby contrives to lodge a quantity of the sand upon the head as well as the jaws. The motion is in fact something like that of the head of a goat, especially when butting sideways in play. In this manner it contrives to throw away the sand, and by degrees to make a hole entirel}^ with its head, the four legs not aflbrding the slightest assistance in the operation. During this per- formance the head only is exposed, the insect having previousl}' pushed itself beneath the surface of the sand ; but when it has made the hole sufficiently deep, it with- draws the head also, leaving only the jaws exposed, which are spread open in a line, and laid on the sand so as to be scarcely visible. If alarmed, the insect imme- diately takes a step backwards, withdrawing the jaws ; but when an insect falls into the hole, the jaws are in- stinctively and instantaneously closed, and the insect seized by the leg, wing, or body, just as it may chance 1o fall within the reach of the ant-lion's jaws. If, how- ever, the insect be not seized, but attempts to escape, no matter in what direction, the ant-lion immediately begins twisting its head about, and shovelling up the sand with the greatest agility, jerking it about on each side and backwards, but never forwards, as misrepresented in some figures, until the hole is made so much deeper, and such a disturbance caused in the sides of the hole, THE ANT-LIOX. 201 that the insect is almost sure to be brought down to the bottom, when it is seized by the ant-lion, which imme- diately endeavours to draw it beneath the sand ; and if it be very boisterous, the ant-lion beats it about, holding it firmly with the jaws, until it is too weak for further re- sistance. Hence, as the head of the ant-lion is immersed in the sand, it is evident that the accounts given in po- pular works of the instinct by which it throws the sand in the direction of the escaping prey is not quite correct. The act of throwing up the sand, when an insect has fallen into the pit and attempts to escape, has evidently for its chief object that of making the pit deeper and more conical, and therefore more difficult of ascent." It is by the action of the hinder pair of its legs that the ant-lion drags itself backwards, the other four pair being extended trailing after it, and leaving an impression on the surface of the fine sand over which it has passed ; and when burrowing its way beneath the surface of the sand, it proceeds by short steps backwards. A portion of sand at each step is thrown on the head, owing to the hump-like form of the back ; this is immediately jerked away, the body at the same time advancing another step in its backward and spiral motion. Where it rests, a little hillock of sand is raised by the body of the ant-lion underneath ; while its jaws emerge and spread flat on the surface. It now probably commences its pitfall, the mode of excavating which we have given in detail. From the spiral course described by the ant-lion in its backward progress, ajjpears to have arisen the idea of its tracing out a circle as the outline of its pitfall — as Mould an architect or engineer ; but whence sprang the often- repeated statement, that the ant-lion loads its head with sand by means of one of its legs, that nearest the centre of the circle, we cannot conjecture. Nor do we know how, as it works entirely buried with the exception of the head, the ant-lion can act when it meets with a stone or other obstacle, as M. Bonnet states he has repeatedly witnessed. He observes that if the stone be small, it can manage to jerk it out in the same manner as the sand ; but when it is two or three times larger and heavier than VOL. I. K 202 IXSECT ARCHITECTUKE. Aut-Lion's Pitfalls, in an expeiimenting-box. its own body, it must have recourse to other means of removal. The larger stones it usually leaves till the last ; and when it has removed all the sand which it intends, it then proceeds to try what it can do with the less manage- able obstacles. For this purpose, it crawls backwards to the place where a stone may be, and thrusting its tail under it, is at great pains to get it properly balanced on its back, by an alternate motion of the rings composing its body. When it has succeeded in adjusting the stone, it crawls up the side of the yi'it with great care, and de- posits its burthen on the outside of the circle. Should the stone happen to be round, the balance can be kept only with the greatest difficulty, as it has to travel with its load upon a slope of loose sand which is ready to give way at every step ; and often when the insect has carried it to the very brink, it rolls off its back and tumbles down to the bottom of the pit. This accident, so far from dis- couraging the ant-lion , only stimulates it to more perse- vering efforts. Bonnet observed it renew these attempts to dislodge a stone five or six times. It is only when it finds it utterly impossible to succeed, that it abandons the design and commences another pit in a fresh situation. When it succeeds in getting a stone beyond the line of its circle, it is not contented with letting it rest there ; but to prevent it from again rolling in, it goes on to push it to a considerable distance. We may be pardoned for pausing before we give full credence to these details. The ant-lion feeds only on the blood or juice of insects ; THE A>'T-LIOir. 203 and as soon as it has extracted these, it tosses the dry- carcase out of its den. When it is about to change into a pupa, it proceeds in nearly the same manner as the caterpillar of the water- betony moth (Caculfia scropl/ularice). It first builds a case of sand, the particles of which are secured by threads of silk, and then tapestries the whole with a silken web. Within this it undergoes its transformation into a pupa, and in due time it emerges in form of a four- winged fly, closely resembling the dragon-flies (^Lihellulce), vulgarly and erroneously called horse-stingers. The instance of the ant-lion naturally leads us to con- sider the design of the Author of Nature in so nicely adjusting, in all animals, the means of destruction and of escape. As the larger quadrupeds of prey are provided with a most ingenious machinery for preying on the weaker, so are these furnished with the most admirable powers of evading their destroyers. In the economy of insects, we constantly observe that the means of defence, not only of the individual creatures, but of their larvas and pupae, against the attacks of other insects, and of birds, is proportioned, in the ingenuity of their arrange- ments, to the weakness of the insect employing them. Those species which multiply the quickest have the greatest number of enemies, Bradley, an English natu- ralist, has calculated that two sparrows carry, in the course of a week, above three thousand caterpillars to the young in their nests. But though this is, probably, much beyond the truth, it is certain that there is a great and constant destruction of individuals going forward ; and yet the species is never destroyed. In this way a balance is kept up, by which one portion of animated nature cannot usurp the means of life and enjoyment which the world offers to another portion. In all matters relating to reproduction. Nature is prodigal in her ar- rangements. Insects have more stages to pass through be- fore they attain their perfect growth than other creatures. The continuation of the species is, therefore, in many cases, provided for by a much larger number of eggs being deposited than ever become fertile. How many k2 204 IKSECT ARCHITECTURE. larvae are produced, in comparison with the number which pass into the pupa state ; and how many pupae perish before they become perfect insects ! Every garden is covered with caterpillars ; and yet how few moths and butterflies, comparatively, are seen, ev'cn in the most sunny season ! Insects which lay few eggs are, commonly, most remarkable in their contrivances for their preserva- tion. The dangers to which insect life is exposed arc manifold ; and therefore are the contrivances for its pre- servation of the most perfect kind, and invariably adapted to the peculiar habits of each tribe. The same wisdom determines the food of every species of insect ; and thus some are found to delight in the rose-tree, and some in the oak. Had it been otherwise, the balance of vegetable life would not have been preserved. It is for this reason that the contrivances which an insect employs for obtain- ing its food are curious, in proportion to the natural difficulties of its structure. The ant-lion is carnivorous, but he has not the quickness of the spider, nor can he spread a net over a large surface, and issue from his citadel to seize a victim which he has caught in his out- works. He is therefore taught to dig a trap, where he sits, like the unwieldy giants of fable, waiting for some feeble one to cross his path. How laborious and patient are his operations — how uncertain the chances of success ! Yet he never shrinks from them, because his instinct tells him that by these contrivances alone can he preserve his own existence, and continue that of his species. ( 205 ) CHAPTER XII. Clothes-Moth and other Tent-making Caterpillars. — Leaf and Bark Miners. There are at least five different species of moths similar in manners and economy, the caterpillars of which feed upon animal substances, such as furs, woollen cloths, silk , leather, and, what to the naturalist is no less vexing, upon the specimens of insects and other animals pre- served in his cabinet. The moths in question are of the family named Tinea by Entomologists, such as the tapestry moth {Tinea tapetzella), the fur moth {Tinea pellionella), the wool moth {Tinea vestianella), the cabinet moth {Tinea destructor, Stephens), &c. The moths themselves are, in the winged state, small, and well fitted for making their way through the most minute hole or chink, so that it is scarcely possible to exclude them by the closeness of a wardrobe or a cabinet.* If they cannot effect an entrance when a drawer is out, or a door open, they will contrive to glide through the key-hole ; and if they once get in, it is no easy matter to dislodge or destroy them, for they are exceedingly agile, and escape out of sight in a moment. Moufet is of opinion that the ancients possessed an effectual method of preserving stuffs from the moth, because the robes of Servius Tullius were preserved up to the death of Sejanus, a period of more than five hundred years. On turning to Pliny to learn this secret, we find him relating that stuff" laid upon a coffin will be ever after safe from moths ; in the same way as a person once stung by a scorpion will never afterwards be stung by a bee, or a wasp, or a hornet ! Rhasis again says, * See fig. (/., p. 209. 206 INSECT ARCHITECTURE. that cantharides suspended in a house drive away moths ; and, he adds, that they will not touch anything wrapped in a lion's skin ! — the poor little insects, says Reaumur sarcastically, being probably in bodily fear of so terrible an animal.* Such are the stories which fill the imagina- tion even of philosophers, till real science entirely expels them. The effluvium of camphor or turpentine, or fumiga- tion by sulphur or chlorine, may sometimes kill them, when in the winged state, but this will have no effect upon their eggs, and seldom upon the caterpillars ; for they wrap themselves up too closely to be easily reached by any agent except heat. This, '^when it can be con- veniently applied, Mall be certain either to dislodge or to kill them. When the effluvium of turpentine, how- ever, reaches the caterpillar. Bonnet says it falls into convulsions, becomes covered with livid blotches, and dies.f The mother insect takes care to deposit her eggs on or near such substances as she instinctively foreknows will be best adapted for the food of the young, taking care to distribute them so that there may be a plentiful supply and enough of room for each. We have found, for example, some of those caterpillars feeding upon the shreds of cloth used in training wall-fruit trees ; but we never saw more than two caterpillars on one shred. This scattering of the eggs in many places renders the effects of the caterpillars more injurious, from their attacking many parts of a garment or a piece of stuff at the same time. (J. R.) When one of the caterpillars of this family issues from the egg^ its first care is to provide itself with a domicile, which indeed seems no less indispensable to it than food ; for, like all caterpillars that feed under cover, it will not eat while it remains unprotected. Its mode of building is very similar to that which is employed by other cater- pillars that make use of extraneous materials. The * Reaumur, ' Mem. Hist. Insectes,' iii. 70. •j- ' Contemplation de la Nature,' part xii. chap. x. note. MOTH-CATERPILLARS. 207 foundation or frame-work is made of silk secreted by itself, and into this it interweaves portions of the material upon which it feeds. It is said by Bingley, that " after having spun a fine coating of silk immediately around its hodi/, it cuts the filaments of the wool or fur close by the thread of the cloth, or by the skin, with its teeth, which act in the manner of scissors, into convenient lengths, and applies the bits, one by one, with great dexterity, to the outside of its silken case." * This statement, however, is erroneous, and inconsistent with the proceedings not only of the clothes-moth, but of every caterpillar that constructs a covering. None of these build from within outwards, but uniformly com- mence with the exterior wall, and finish by lining the interior with the finest materials. Reaumur, however, found that the newly-hatched caterpillars lived at first in a case of siik. We have repeatedly witnessed the proceedings of these insects from the very foundation of their structures ; and, at the moment of writing this, w'e turned out one from the carcase of an " old lady moth " (^Mormo maura, Ochsex- heim) in our cabinet, and placed it on a desk covered with green cloth, where it might find materials for con- structing another dwelling. It wandered about for half a day before it began its operations ; but it did not, as is asserted by Bonnet, and Kirby and Spence, " in mov- ing from place to place, seem to be as much incom- moded by the long hairs which surround it, as we are by walking amongst high grass," nor, "accordingly, march- ing scythe in hand," did it, " with its teeth, cut out a smooth road." f On the contrary, it did not cut a single hair, till it selected one for the foundation of its in- tended structure. This it cut very near the cloth, in order, we suppose, to have it as long as possible ; and placed it on a line with its body. It then immediately cut another, and placing it parallel to the first, bound both together with a few threads of its own silk. The * 'Animal Biograjliy,' vol. iii. p. 330, 3d ed. t Bonnet, xi. p. 204; Kirby and Spence, 'Intro.' i. 46 J, 5th ed. 208 I^-SECT ARCHITECTURE. same ])rocess was repeated with other hairs, till the little creature had made a fabric of some thickness, and this it went on to extend till it was large enough to cover its body ; which (as is usual with caterpillars) it employed as a model and measure for 2'egulating its operations. We remarked that it made choice of longer hairs for the outside than for the parts of the interior, which it thought necessary to strengthen by fresh additions ; but the chamber was ultimately finished by a fine and closely woven tapestry of silk. We could see the progress of its work, by looking into the opening at either of the ends ; for at this stage of the structure the walls are quite opaque, and the insect concealed. It may be thus ob- served to turn round, by doubling itself and bringing its head where the tail had just been ; of course, the interior is left wide enough for this purpose, and the centre, indeed, where it turns, is always wider than the extre- mities. (J. R.) When the caterpillar increases in length, it takes care to add to the length of its house, by working-in fresh hairs at either end ; and if it be shifted to stuffs of dif- ferent colours, it may be made to construct a party- coloured tissue, like a Scotch plaid. Reaumur cut off with scissors a portion at each end, to compel the insect to make up the deficiency. But the caterpillar increases in thickness as well as in length, so that, its first house becoming too narrow, it must either enlarge it, or build a new one. It prefers the former as less troublesome, and accomplishes its purpose " as dexterously," says Bonnet, '* as any tailor, and sets to work precisely as we should do, slitting the case on the two opposite sides, and then adroitly inserting between them two pieces of the requisite size. It does not, however, cut open the case from one end to the other at once ; the sides would separate too far asunder, and the insect be left naked. It therefore first cuts each side about half way down, beginning senietimes at the centre and sometimes at the end (Fig. c), and then, after having filled up the fissure, proceeds to cut the remaining half; so that, in fact, four enlargements are made, and four separate pieces inserted. The colour of the case is always the MOTH-CATERPILLARS. 209 Cases, Sec, of the Clothes-Moth (Tinea pellioneUa). — n. Caterpillar feed- ing ill a case, \v}\ichhas been lengthened by ovals of different colours; b, Case cut at tlie ends for expeiimeut; c. Case cut open by the insect for enlarging it ; d, e. The clothes-moths in their perfect state, when, as they cease to eat, they do no furtiier injury. same as that of the stuft'from ^vhich it is taken. Thus, if its original colour be blue, and the insect, previously to enlarging it, be put upon red cloth, the circles at the end, and two stripes down the middle, will be red." * Reaumur found that they cut these enlargements in no precise order, but sometimes continuously, and some- times opposite each other, indifferently. The same naturalist says he never knew one leave its old dwelling in order to build a new, though, when once ejected by force from its house, it would never enter it again, as some other species of caterpillars will do, but always preferred building another. We, on the con- trary, have more than once seen them leave an old habi- tation. The very caterpillar, indeed, whose history we have above given, first took up its abode in a specimen of the ghost-moth (Hejnalus hiunuli), where, finding few suit- able materials for building, it had recourse to the cork of the drawer, with the chips of which it made a structure * Bonnet, vol. ix. p. 203. K o 210 I>'SECT ARCHITECTURE. almost as warm as it would have done from wool. Whether it took offence at our disturbing it one day, or whether it did not find sufficient food in the body of the ghost-moth, we know not ; but it left its cork house, and travelled about eighteen inches, selected " the old lady," one of the largest insects in the drawer, and built a new apartment composed partly of cork as before, and partly of bits dipt out of the moth's wings. (J. R.) We have seen these caterpillars form their habitations of every sort of insect, from a butterfly to a beetle ; and the soft feathery wings of moths answer their purpose very well : but when they fall in with such hard ma- terials as the musk beetle {Ceramhyx moschatus) or the large scolopendra of the West Indies, they find some difficulty in the building. When the structure is finished, the insect deems itself secure to feed on the materials of the cloth or other animal matter within its reach, provided it is dry and free from fat or grease, wliich Reaumur found it would not touch. This may probably be the origin of the practice of putting a bit of candle with furs, &c., to pre- serve them from the moth. For building, it always selects the straightest and loosest pieces of wool, but for food it prefers the shortest and most compact ; and to procure these it eats into the body of the stuif, rejecting the pile or nap, which it necessarily cuts across at the origin, and permits to fall, leaving it threadbare, as if it had been much worn. It must have been this circum- stance which induced Bonnet to fancy (as we have al- ready mentioned) that it cut the hairs to make itself a smooth comfortable path to walk upon. It would be equally correct to say that an ox or a sheep dislikes walking amongst long grass, and therefore eats it down in order to clear the wa}^ TENT-MAKING CATERPILLARS. The caterpillars of a family of small moths {Tineidc^}, which feed on the leaves of various trees, such as the haw- thorn, the elm, the oak, and most fruit-trees, particu- TENT-MAKING CATERPILLARS. 211 larly the pear, form habitations which are exceedingly ingenious and elegant. They are so very minute that they require close inspection to discover them ; and to the _ cursory observer, unacquainted uith their habits, they will appear more like the withered leaf scales of the tree, thrown off when the buds expand, than artificial structures made by insects. It is only, indeed, by seeing them move about upon the leaves, that we discover they are inhabited by a living tenant, who carries them as the snail does its shell. These tents are from a quarter of an inch to an inch in length, and usually about the breadth of an oat-straw. That they are of the colour of a withered leaf is not surprising ; for they are actually composed of a piece of leaf; not, hovvever, cut out from the whole thickness, but artfully separated from the upper layer, as a person might separate one of the leaves of paper from a sheet of pasteboard ; K^M^_ A caterpillar's tent upon a leaf of the elm. — a, a, the part of the leaf from Nvhich the tent has been cut out ; b, the tent itself. The tents of this class of caterpillars, which are found on the elm, the alder, and other trees with serrated leaves, are much in the shape of a minute gold-fish. They are convex on the back, where the indentations of the leaf out of which they have been cut add to the resemblance, by appearing like the dorsal fins of the fish. By depriv- ing one of those caterpillars common on the hawthorn of its tent, for the sake of experiment, we put it under the necessity of making another ; for, as Fliny remarks of the clothes-moth, they will rather die of hunger than 212 INSECT ARCHITECTURE. feed unprotected. When we placed it on a fresh haw- thorn leaf, it re})eatedly examined every part of it, as if seeking for its lost tent, though, when this was put in its way, it would not again enter it ; but, after some delay, commenced a new one. (J. R.) For this purpose, it began to eat through one of the two outer membranes which compose the leaf and enclose the pulp {parencliymo) ^ some of which, also, it devoured, and then thrust the hinder part of its body into the per- foration. The cavity, however, which it had formed, being yet too small for its reception, it immediately re- sumed the task of making it larger. By continuing to gnaw into the pulp, hehveen the membranes of the leaf (for it took the greatest care not to puncture or injure the membranes themselves), it soon succeeded in mining out a gallery rather larger than was sufficient to contain its body. We perceived that it did not throw out as rubbish the pulp it dug into, but devoured it as food, — a circumstance not the least remarkable in its proceedings. As the two membranes of leaf thus deprived of the enclosed pulp appeared white and transparent, every movement of the insect within could be distinctly seen ; and it was not a little interesting to watch its ingenious operations while it was making its tent from the mem- branes prepared as we have just described. These, as Reaumur has remarked, are in fact to the insect like a piece of cloth in the hands of a tailor ; and no tailor could cut out a shape with more neatness and dexterity than this little workman does. As the caterpillar is furnished in its mandibles with an excellent pair of scissors, this may not appear to be a difficult task ; yet, when wc examine the matter more minutely, we find that the peculiar shape of the two extremities requires different curvatures, and this, of course, renders the operation no less complex, as Reaumur subjoins, than the shaping of the pieces of cloth for a coat.* The insect, in fact, shapes the mem- branes slightly convex on one side and concave on the other, and at one end twice as large as at the other. In the instance which we observed, beginning * ♦ Mem. Hist. Insect.' iii. p. 106. TENT-MAKIJfG CATEBPILLARS. 213 at the larger end, it bent them gently on each side by pressing them with its body thrown into a curve. We have not said it cuts, but shapes its materials ; for it must be obvious that if the insect had cut both the mem- branes at this stage of its operations, the pieces would have fallen and carried it along with them. To obviate such an accident it proceeded to join the two edges, and secure them firmly with silk, before it made a single incision to detach them. When it had in this manner joined the two edges along one of the sides, it inserted its head on the outside of the joining, first at one end and then at the other, gnawing the fibres till that whole side was separated. It proceeded in the same manner with the other side, joining the edges before it cut them ; and when it arrived at the last fibre, the only remaining support of its now finished tent, it took the precaution, before snipping it, to moor the whole to the uncut part of the leaf by a cable of its own silk. Con- sequently, when it does cut the last nervure, it is secure from falling, and can then travel along the leaf, carrying its tent on its back, as a snail does its shell. (J. R.) a. The Caterpillar occupying the space it has eaten between tire cuticle of t!:e leaf; b, A portion of the upper cuticle, cut out for the formation of the tent; c, The tent nearly completed ; d. The perfect tent, with the caterpillar protruding its head. We have just discovered (Nov. 4th, 1829) upon the nettle a tent of a very singular appearance, in conse- 214 INSECT ARCHITECTURE. quence of the materials of which it is made. The cater- pillar seems, indeed, to have proceeded exactly in the same manner as those which we have described, mining first between the two membranes of the leaf, and then uniting these and cutting out his tent. But the tent itself looks singular from being all over studded with the stinging bristles of the nettle, and forming a no less for- midable coat of mail to the little inhabitant than the spiny hide of the hedgehog. In feeding it does not seem to have mined into the leaf, but to have eaten the whole of the lower membrane, along with the entire pulp, leaving nothing but the upper membrane un- touched. (J.R.) During the summer of 1830 we dis- covered a very large tent M'hich had been formed out of a blade of grass ; and another stuck all over with chips of leaves upon the common maple. Tents of Stone-Mason Caterpillars. The caterpillar of a small moth (Tinea) which feeds upon the lichens growing on walls, builds for itself a moveable tent of a very singular kind. M. de la Voye was the first who described these insects ; but though they are frequently overlooked, from being very small, they are by no means uncommon on old walls. Reaumur observed them regularly for twenty years together on the terrace- wall of the Tuileries at Paris ; and they may be found in abundance in similar situations in this country. This accurate obsei'ver refuted by experiment the notion of M. de la Voye that the caterpillars fed upon the stones of the wall ; but he satisfied himself that they detached particles of the stone for the purpose of building their tents or sheaths (foun-eaux), as he calls their dwellings. In order to watch their mode of building, Reaumur gently ejected half a dozen of them from their homes, and observed them detach grain after grain from a piece of stone, binding each into the wall of their building with silk till the cell acquired the requisite magnitude, the whole operation taking' about twenty-four hours of con- tinued laboiu-. M. de la Voye mentions small granular STOXE-MASON CATERPILLARS. 215 bodies of a greenish colour, placed irregularly on the exterior of the structure, which he calls eggs ; but we agree with Reaumur in thinking it more probable that they are small fragments of moss or lichen intermixed with the stone : in lact, we have ascertained that they are so. (J. R.) When these little architects prepare for their change into chrysalides before becoming moths, they attach their tents securely to the stone over which they have hitherto i-ambled, by spinning a strong mooring of silk, so as not only to till up every interstice between the main entrance of the tent and the stone, but also weaving a close, thick curtain of the same material, to shut up the entire aperture. Licheii-Tenta and Caterpillars, both of their natural size and magnified.' It is usual for insects which form similar structures to issue, when they assume the winged state, from the broader end of their habitation ; but our little stone- mason proceeds in a different manner. It leaves open the apex of the cone from the first, for the purpose of ejecting its excrements, and latterly it enlarges this opening a little, to allow of a free exit when it acquires W'ings ; taking care, however, to spin over it a canopy of„ silk, as a temporary protection, which it can afterwards burst through without difficulty. The moth itself is very much like the common clothes-moth in form, but is of a gilded bronze colour, and considerably smaller. 216 INSECT ARCHITECTURE. ' In the same locality, M. de Maupertuis found a nume- rous brood of small caterpillars, which employed grains of stone, not, like the preceding:, for building feeding tents, but for their cocoons. This caterpillar was of a brownish-grey colour, with a white line along the back, on each side of which were tufts of hair. The cocoons which it built were oval, and less in size than a hazel nut, the grains of the stone being skilfully woven into irregular meshes of silk. In June, 1829, we found a numerous encampment of the tent-building caterpillars described by MM. de la Voye and Reaumur, on the brick wall of a garden at Blackheath, Kent. (J. R.) They were so very small, however, and so like the lichen on the wall, that, had not our attention been previously directed to their habits, we should have considered them as portions of the wall ; for not one of them was in motion, and it was only by the neat, turbi- nated, conical form in which they had constructed their habitations, that we detected them. We tried the ex- periment above-mentioned, of ejecting one of the cater- pillars from its tent, in order to watch its proceedings when constructing another ; but probably its haste to procure shelter, or the artificial circumstances into which it was thrown, influenced its operations, for it did not form so good a tent as the first, the texture of the walls being much slighter, while it was more rounded at the apex, and of course not so elegant. Reaumur found, in all his similar experiments, that the new structure equalled the old ; but most of the trials of this kind which we have made correspond with the inferiority which we have here recorded. The process indeed is the same, but it seems to be done with more hurry and less care. It may be, indeed, in some cases, that the supply of silk necessary to unite the bits of stone, earth, or lichen employed, is too scanty for perfecting a second struc- ture. We remarked a very singular circumstance in the operations of our little architect, which seems to have escaped the minute and accurate attention of Reaumur. When it commenced its structure, it was indispensable STONE-MASON CATERPILLARS. 217 to lay a foundation for the walls about to be reared ; but as the tent was to be moveable like the shell of a snail, and not stationary, it would not have answered its end to cement the foundation to the wall. We had fore- seen this difficulty, and felt not a little interested in discovering how it would be got over. xVccordingly, upon watching its movements with some attention, we were soon gratified to perceive that it used its own body as the primary support of the building. It fixed a thread of silk upon one of its right feet, warped it over to the corresponding left foot, and upon the thread thus stretched between the two feet it glued grains of stone and chips of lichen, till the wall was of the required thickness. Upon this, as a foundation, it continued to work till it had formed a small portion in form of a parallelogram ; and, proceeding in a similar way, it was not long in making a ring a very little wider than sufficient to admit its body. It extended this ring in breadth, by working on the inside only, narrowing the diameter by degrees, till it began to take the form of a cone. The apex of this cone was not closed up, but left as an aperture through which to eject its excrements. It is worthy of remark, that one of the caterpillars which we deprived of its tent, attempted to save itself the trouble of building a new one, by endeavouring to unhouse one of its neighbours. For this purpose, it got upon the outside of the inhabited tent, and, sliding its head down to the entrance, tried to make its M'ay into the interior. But the rightful owner did not choose to give up his premises so easily ; and fixed his tent down so firmly upon the table where we had placed it, that the intruder was forced to abandon his attempt. The in- stant, however, that the other unmoored his tent and began to move about, the invader renewed his efibrts to eject him, persevering in the struggle for several hours, but without a chance of success. At one time we imagined that he would have accomplished his felonious intentions ; for he bound down the apex of the tent to the table with cables of silk. But he attempted his entrance at the wrong end. He ought to have tried the 218 INSECT ARCHITECTURE. aperture in the apex, by enlarging which a little he would undoubtedly have made good his entrance ; and as the inhabitant could not have turned upon him for want of room, the castle must have been sun'endered. This experiment,' however, was not tried, and -there was no hope for him at the main entrance. Muff-shaped Tents. The ingenuity of man has pressed into his service not only the wool, the hair, and even the skins of animals, but has most extensively searched the vegetable king- dom for the materials of his clothing. In all this, how- ever, he is rivalled by the tiny inhabitants of the insect world, as we have already seen ; and we are about now to give an additional instance of the art of a species of caterpillars which select a warmer material for their tents than even the caterpillar of the clothes- moth. It may have been remarked by many who are not botanists, that the seed-catkins of the willow become, as they ripen, covered with a species of down or cotton, which, how- ever, is too short in the fibre to be advantageously em- ployed in our manufactures. But the caterpillars to which we have alluded, find it well adapted for their habitations. The muft-looking tent in which we find these insects does not require much trouble to construct ; for the ca- terpillar does not, like the clothes-moth caterpillar, join the willow-cotton together, fibre by fibre — it is contented with the state in which it finds it on the seed. Into this it burrows, lines the interior with a tapestry of silk, and then detaches the whole from the branch where it was growing, and carries it about with it as a protection while it is feeding.* ^ An inquiring friend of Reaumur having found one of these insects floating about in its muff-tent upon water, concluded that they fed upon aquatic plants ; but he was soon convinced that it had only been blown down by an * Reaumur, iii. p. 130. MINING CATERPILLARS. 219 a, Brancli of the Wil ow, with seed spikes covered with eottou ; 6, Muff Tents, made of this cotton by c, the Caterpillar. accident, %vhich must frequently happen, as willows so often hang over water. May it not be, that the buoyant materials of the tent were intended to furnish the little inhabitant with a life-boat, in which, when it chanced to be blown into the water, it might sail safely ashore and resrain its native tree ? Leaf-mixixg Caterpillars. The process of mining between the two membranes of a leaf is carried on to more extent by minute caterpillars allied to the tent-makers above described. The tent- maker never deserts his house, except when compelled, and therefore can only mine to about half the length of his own body ; but the miners now to be considered 220 rsSECT ARCHITECTUKE. make the mine itself their dwelling'-placc, and as they eat their way they lengthen and enlarge their galleries. A few of these mining caterpillars are the progeny of small weevils {Ciirculionidce) , some of two- winged flies (^Diptera) J but the greater number are produced from a genus of minute moths {(Ecophora, Latr.), which, when magnified, appear to be amongst the most splendid and brilliant of Nature's productions, vying even with the humming-birds and diamond beetles of the tropics in the rich metallic colours which bespangle their wings. Well may Bonnet call them " tiny miracles of nature," and regret that they are not en grand* There are few plants or trees whose leaves may not, at some season of the year, be found mined by these caterpillars, the track of whose progress appears on the upper surface in winding lines. Let us take one of the Leaf of the Monthly Rose {Rose Indica'), mined by Caterpillars of Argyioiuiges ? most common of these for an example,— that of the rose- leaf, produced by the caterpillar of Ray's golden-silver spot {Argyromifjcs Rcnjella? Curtis), of which we have * Bonnet, * Contempl. de la Nature,' part xii. MINING CATEKPILLARS. 221 just gathered above a dozen specimens from one rose- tree. (J. II.) It may be remarked that the winding line is black, closely resembling the tortuous course of a river on a map, — beginning like a small brook, and gradually in- creasing in breadth as it proceeds. This representation of a river exhibits, besides, a narrow white valley on each side of it, increasing as it goes, till it terminates in a broad delta. The valley is the portion of the inner leaf from which the caterpillar has eaten the pulp (^paren- chyma), while the river itself has been formed by the liquid ejectamenta of the insect, the watery part be- coming evaporated. In other species of miners, how- ever, the dung is hard and dry, and consequently these only exhibit the valley without the river (see p. 223). On looking at the back of the leaf, where the wind- ing line begins, we uniformly find the shell of the very minute e^^ from which the caterpillar has been hatched, and hence perceive that it digs into the leaf the moment it escapes from the ^^^^ without wandering a hair's breadth from the spot ; as if afraid lest the air should visit it too roughly. The e^^ is, for the most part, placed upon the mid-rib of the rose-leaf, but some- times on one of the larger nervures. When once it has got within the leaf, it seems to pursue no certain direc- tion, sometimes working to the centre, sometimes to the circumference, sometimes to the point, and sometimes to the base, and even, occasionally, crossing or keeping parallel to its own previous track. The most marvellous circumstance, however, is the minuteness of its workmanship ; for though a rose-leaf is thinner than this paper, the insect finds room to mine a tunnel to live in, and plenty of food, without touching the two external membranes. Let any one try with the nicest dissecting instruments to separate the two plates of a rose-leaf, and he will find it impossible to proceed far without tearing one or other. The caterpillar goes still further in minute nicety ; for it may be remarked, that its track can only be seen on the upper, and not on the under surface of the leaf, proving that it eats as it pro- 222 INSECT ARCHITECTURE. ceeds only half the thickness of the pulp, or that portion of it which belongs to the upper membrane of the leaf. We have found this liitle miner on almost every sort of rose-tree, both wild and cultivated, including the sweet-briar, in which the leaf being very small, it re- quires nearly the whole parenchyma to feed one cater- pillar. They seem, however, to prefer the foreign monthly rose to any of our native species, and there are few trees of this where they may not be discovered. Tunnels very analogous to the preceding may be found upon the common bramble (Mubus fruticosus) ; and on the holly, early in spring, one which is in form of an irregular whitish blotch. But in the former case, the little miner seems to proceed more regularly, always, when newly hatched, making directly for the circum- ference, upon or near which also the mother moth depo- sits her Q^g^ and winding along for half the extent of the leaf close upon the edge, following, in some cases, the very indentations formed by the terminating nervures. Leaf of tlie Dew-berry Bramble (Ruhus ccesiuij, mined by Caterpillars. The bramble-leaf miner seems also to differ from that of the rose-leaf, by eating the pulp both from the upper and under surface, at least the track is equally distinct above and below ; yet this may arise from the different MINING CATERPILLARS. 223 consistence of the leaf pulp, that in the rose being firm, while that of the bramble is soft and pufty. On the leaves of the common primrose (^Primula veris), as well as on the garden variety of it, the polyanthus, one of those mining caterpillars may very frequently be found. It is, however, considerably dif- ferent from the preceding, for there is no black trace — no river to the valley which it excavates : its ejecta- menta, being small and solid, are seen, when the leaf is dried, in little black points like grains of sand. This miner also seems more partial than the preceding to the mid-rib and its vicinity, in consequence of which its path is seldom so tortuous, and often appears at its extremity to terminate in an area, comparatively extensive, arising from its recrossing its previous tracks. (J. R.) Leaf of the Primrose (^Primula veris), mined by a Caterpillar. Svtammerdam describes a mining caterpillar which he found on the leaves of the alder, though it did not, like those we have just described, excavate a winding gallery ; it kept upon the same spot, and formed only an irregular area. A moth was produced from this, whose upper wings, he says, " shone and glittered most gloriously with crescents of gold, silver, and brown, surrounded by borders of delicate black." Another area miner which he found on the leaves of willows, as many as seventeen on one leaf, producing what appeared to be rusty spots, was metamorphosed into a very minute weevil ( Carculio 224 INSECT ARCUITECTUKE. RJunoc). He says he has been informed, that, in warm climates, worms an inch long are found in leaves, and adds, with great simplicity, " on these many fine expe- riments might have been made, if the inhabitants had not laboured under the cursed thirst of gold."* The vine-leaf miner, when about to construct its cocoon, cuts, from the termination of its gallery, two pieces of the membrane of the leaf, deprived of their pulp, in a similar manner to the tent-makers described above, uniting them and lining them with silk. This she carries to some distance before she lays herself up to undergo her change. Her mode of walking under her burthen is peculiar, for, not contented with the security of a single thread of silk, she forms, as Bonnet says, " little mountains {monticules) of silk, from distance to distance, and seizing one of these with her teeth, drags herself forward, and makes it a scaffolding from which she can build another.f Some of the miners, however, do not leave their galleries, but undergo their transforma- tions there, taking the precaution to mine a cell, not in the upper, but in the under surface ; others only shift to another portion of the leaf. Social LEAF-MI^'ERs. The preceding descriptions apply to caterpillars who construct their mines in solitude, there being seldom more than one on a leaf or leaflet, unless when two mother flies happen to lay their eggs on the same leaf; but there are others, such as the miners of the leaves of the henbane {Hyoscyanms niger)^ which excavate a common area in concert — from four to eight forming a colony. These are very like flesh-maggots, being larger than the common miners ; the leaves of this plant, from being thick and juicy, giving them space to work and plenty to eat. Most of the solitary leaf-miners either cannot or will * Swammerd., < Book of Nature,' vol. ii. p. 84. f ' Contempl. de la Nature/ part xii. p. 197. BAEK-MINIKG CATERPILLARS. 225 not construct a new mine, if ejected by an experimenter from the old, as we have frequently ])roved ; but this is not the case with the social miners of the henbane leaf. Bonnet ejected one of these, and watched it with his glass till it commenced a new tunnel, which it also en- larged with great expedition ; and in order to verify the assertion of Reaumur, that they neither endeavour nor fear to meet one another, he introduced a second. Neither of them manifested any knowledge of the other's contiguity, but both worked hard at the gallery, as did a third and a fourth which he afterwards introduced ; for though they seemed uneasy, they never attacked one another, as the solitary ones often do when they meet.* Bark-m!nixg Caterpillars. A very different order of mining caterpillars are the progeny of various beetles, which excavate their galleries in the soft inner bark of trees, or between it and the young wood {alburnum). Some of these, though small, commit extensive ravages, as may readily be conceived when we are told that as many as eighty thousand are occasionally found on one tree. In 1783 the trees thus destroyed by the printer-beetle {Tomictts typographus^ Latr.), so called from its tracks resembling letters, amounted to above a million and a half in the Hartz forest. It appears there periodically, and confines its ravages to the iir. This insect is said to have been found in the neighbourhood of London. On taking off the bark of decaying poplars and wil- lows, we have frequently met with the tracks of a miner of this order, extending in tortuous pathways, about a quarter of an inch broad, for several feet and even yards in length. The excavation is not circular, but a com^ pressed oval, and crammed throughout with a dark- coloured substance like sawdust — the excrement no doubt of the little miner, who is thereby protected from the attacks of Staphylinidce, and other predaceous insects, * Bonnet, ' Observ. sur les Insectes, vol. ii. p. 425. VOL. I. L 226 INSECT ARCHITECTURE. from behind. But though we have found a great nuiff- ber of these subcortical tracks, we have never discovered one of the miners, though they are very probably the grubs of the pretty musk-beetle (^Ceramhyx ynoschatus), which are so abundant in the neighbourhood of the trees in question, that the very air in summer is perfumed with their odour. (J. R.) Another Capricorn beetle of this family is no less de- structive to bark in its perfect state than the above are when grubs, as from its habit of eating round a tree, it cuts the course of the returning sap, and destroys it. C.'.pricoru Beetle (Ceramhyx Lamia ampulatvr) rounding off the balk of a tree, MOLE-CRICKET. 227 CHAPTER XIII. Structures of Grasshoppers, Crickets, and Beetles. Grasshoppers, locusts, crickets, and beetles arc, in many respects, no less interesting than the insects whose architectural proceedings we have already detailed. They do not, indeed, build any edifice for the accom- modation of themselves or their progeny ; but most, if not all of them, excavate retreats in walls or in the ground. The house-cricket (^Acheta domesticd) is well known for its habit of picking out the mortar of ovens and kitchen fire-places, where it not only enjoys warmth, but can procure abundance of food. It is usually supposed that it feeds on bread. M. Latreille says it only eats insects, and it certainly thrives well in houses infested by the cockroach ; but we have also known it eat and destroy lamb's-wool stockings, and other woollen stuffs, hung near a fire to dry. It is evidently not fond of hard labour, but prefers those places where the mortar is already loosened, or at least is new, soft, and easily scooped out; and in this way it will dig covert ways from room to room. In summer, crickets often make excursions from the house to the neighbouring fields, and ^well in the crevices of rubbish, or the cracks made in the ground by diy weather, where they chirp as merrily as in the snuggest chimney corner. Whether they ever dig retreats in such circumstances we have not ascer- tained ; though it is not improbable they may do so for the purpose of making nests. M. Bory St. Vincent tells us that the Spaniards are so fond of crickets that they keep them in cages like singing birds.* * Diet. Classique d'Hist. Nat. Art. Grillon. L 2 228 IXSECT ARCHITECTURE. The Mole-Cricket. The insect, called, from its similarity of habits to the mole, the mole-cricket {Gryllotalpa vulgaris, Latr.) is but too well known in gardens, corn-fields, and the moist banks of rivers and ponds, in some parts of Eng- land, such as Wiltshire and Hampshire, though it is comparatively rare or unknown in others. It burrows in the ground, and forms extensive galleries similar to those of the mole, though smaller ; and these m.ay alv.ays be recognised by a slightly elevated ridge of mould : for the insect does not throw up the earth in hillocks like the mole, but gradually, as it digs along, in the manner of the field-mouse. In this way it commits great ravages, in hotbeds and in gardens, upon peas, young cabbages, and other vegetables, the roots of which it is said to de- vour. It is not improbable, we think, that, like its con- gener, the house-cricket, it may also prey upon under- ground insects, and undermine the plants to get at them, as the mole has been proved to do, Mr. Gould, indeed, fed a mole-cricket for several months upon ants. The structure of the mole-cricket's arms and hands (if we may call them so) is admirably adapted for these ope- rations, being both very strong, an' TENTS. Becfeguar of tlie rose Artichoke gall of the oak . Leaf-gall of Dyer's broom Rose-willow . Rose-hawthorn . , Woolly gall of the oak Experiments with the Flies Oak-apples . . Root-galls of the oak Woody gall of the willow Oak cu riant-galls . W^eevil-Galls Weevil-gall of the hawthorn Anbury on the roots of cabbages, &c. Semi-Galls of Aphides . Mountain- ash leaf-galls Poplar semi-galls of the cottony aphis Leaf-rolling Apliides Leaf of the currant-bush thus alIASO>-A>TS. 11 earth, pilwl up between the stems of the lily without any- apparent cement ; indeed it has been ascertained by Iluber, as we shall afterwards see, that they use no ce- ment beside water. This is not always to be procured, as they depend altogether on rains and dew ; but they possess the art of joining grains of dry sand so as to sup- port one another, on some similar principle, no doubt, to that of the arch. The nest which our turf-ants constructed in the flower- pot was externally of an imperfect square form, in con- sequence of its situation ; for they usually prefer a circular plan. The principal chambers were placed under the arches, and, when inspected, contained a pile of cocoons and pupae. Beneath those upper chambers there were others dug out deeper down, in which were also a numerous collection of eggs and cocoons in various stages of advancement. (J. R.) Mr. Knapp describes a still more curious structure of another species of ant common in this country : — '* One year,*' says he, " on the third of March, my labourer being employed in cutting up ant-hills, or tumps as we call them, exposed to view multitudes of the yellow spe- cies {Formica JIava) in their winter's retirement. They were collected in numbers in little cells and compart- ments, communicating with others by means of narrow passages. In many of the cells they had deposited their larvae, which they were surrounding and attending, but not brooding over or covering. Being disturbed by our rude operations, they removed them IVom our sight to more hidden compartments. The larvae were small. Some of these ant-hills contained multitudes of the young of the wood-louse (Oniscus armadillo), inhabiting with perfect familiarity the same compartments as the ants, crawling about with great activity with them, and per- fectly domesticated with each other. They w ere small and white ; but the constant vibration of their antennae, and the alacrity of their motions, manifested a healthy vigour. The ants were in a torpid state ; but on being removed into a temperate room, they assumed much of their summer's animation. How these creatures are sup- b2 12 INSECT ARCHITECTURE. ported during the winter season it is difficult to compre- hend ; as in no one instance could we perceive any store or provision made for the supply of their wants. The minute size of the larvae manifested that they had been recently deposited ; and consequently that their parents had not remained during winter in a dormant state, and thus free from the calls of hunger. The preceding month of February, and part of January, had been re- markably severe ; the frost had penetrated deep into the earth, and long held it frozen ; the ants were in many cases not more than four inches beneath the surface, and must have been enclosed in a mass of frozen soil for a long period ; yet they, their young, and the onisci, were perfectly uninjured by it : aftbrding another proof of the fallacy of the commonly received opinion, that cold is universally destructive to insect life." * The earth employed by mason -ants is usually moist tlay, either dug from the interior parts of their city, or moistened by rain. The mining-ants and the ash- co- loured {Formica fusca) employ earth which is probably not selected with so much care, for it forms a much coarser mortar than w hat we see used in the structure of the yellow ants {F.JIava) and the brown ants (F. brun- nea). We have never observed them bringing their building materials of this kind from a distance, like the mason -bees and like the wood or hill ant {F. rnfa) ; but they take care, before they fix upon a locality, that it shall produce them all that they require. We are in- debted to Iluber the younger for the most complete ac- count which has hitherto been given of these operations, of which details we sliall make i'vee use. " To form," says this shrewd observer, " a correct judgment of the interior arrangement or distribution of an ant-hill, it is necessary to select such as have not been accidentally spoiled, or whose form has not been too much altered by local circumstances ; a slight atten- tion will then suffice to show that the habitations of the different species are not all constructed after the same ♦ Journal of a Naturalist, p. 30^. MASOX-AXTS. 13 system. Thus, the hillock raised by the ash-coloured ants will always present thick walls, fabricated with coarse earth, well marked stories, and large chambers, with vaulted ceilings, resting upon a solid base. We never observe roads, or galleries, properly so called, but large passages, of an oval form, and all around consider- able cavities and extensive embankments of earth. We I'urther notice, that the little architects observe a certain proportion between the large arched ceilings and the ]jillars that are to support them. " The brown ant {Formica brun?iea), one of the smallest of the ants, is particularly remarkable for the ex- treme finish of its work. Its body is of a reddish shining brown, its head a little deeper, and the antennee and feet a little lighter in colour. The abdomen is of an obscure brown, the scale narrow, of a square form, and slightly scolloped. The body is one line and two-fifths in length.* " This ant, one of the most industrious of its tribe, forms its nest of stories four or five lines in height. The partitions are not more than half a line in thickness ; and the substance of which they are composed is so finely grained, that the inner walls present one smooth unbroken surface. These stories are not horizontal ; they follow the slope of the ant-hill, and lie one upon another to the ground-floor, which communicates with the subterranean lodges. They are not always, however, arranged with the same regularity, for these ants do not follow an in- variable plan ; it aj)pears, on the contrary, that nature has allowed them a certain latitude in this respect, and that they can, according to circumstances, modify them to their wish ; but, however fantastical their habitations may appear, we always observe they have been formed by concentrical stories. On examining each story sepa- rately, we observe a number of cavities or halls, lodges of narrower dimensions, and long galleries, which serve for general communication. The arched ceilings covering the most spacious places are supported either by little co- * A line is the twelfth part of tlie eld French inch. See Companion to the Almanac for 1S30, p. 114. 14 INSECT ARCHITECTURE. liimns, slender walls, or by regular buttresses. We also notice chambers, that have but one entrance, communi- cating with the lower story, and large open spaces, serv- ing as a kind of cross-road (cai-refmir^ , in which all the streets terminate. " Such is the manner in which the habitations of these ants are constructed. Upon opening them, we com- monly find the apartments, as well as the large open spaces, filled with adult ants ; and always observed their pupae collected in the apartments more or less near the surface. This, however, seems regulated by the hour of the day, and the temperature : for in this respect these ants are endowed with great sensibility, and know the degree of heat best adapted for their young. The ant- hill contains, sometimes, more than twenty stories in its upper portion, and at least as many under the surface of the ground. By this arrangement the ants are enabled, with the greatest facility, to regulate the heat. When a too burning sun over-heats their upper apartments, they withdraw their little ones to the bottom of the ant-hill. The ground-floor becoming, in its turn, uninhabitable during the rainy season, the ants of this species transport what most interests them to the higher stories ; and it is there we find them more usually assembled, with their eggs and pupae, when the subterranean apartments are submerged."* Ants have a great dislike to water, when it exceeds that of a light shower to moisten their building materials. One species, mentioned by Azara as indigenous to South America, instinctively builds a nest from three to six feet high,f to provide against the inundations during the rainy season. Even this, however, does not always save them from submersion ; and, when that occurs, they are compelled, in order to prevent themselves from being swept away, to form a group somewhat similar to the curtain of the wax-workers of hive-bees (see vol. i. p. 112). The ants constituting the basis of this group, lay hold of * M. P. Huber on Ants, p. 20. f StedmaiVs Surinam, vol. i., p. 160. MASON-ANTS. 1 5 some shrub for security, while their companions hold on by thoni ; and thus the whole colony, forming an ani- mated raft, floats on the surface of the water till the in- undation (which seldom continues longer than a day or two) subsides. We confess, however, that we are some- what sceptical respecting this story, notwithstanding the very high character of the Spanish naturalist. It is usual with architectural insects to employ some animal secretion, by way of mortar or size, to temper the materials with which they work ; but the whole economy of ants is so different, that it would be wrong to infer from analogy a similarity in this respect, though the exquisite polish and extreme delicacy of finish in their structures, lead, naturally, to such a conclusion. M. P. Huber, in order to resolve this question, at first thought of subjecting the materials of the walls to chemical ana- lysis, but wisely (as we think) abandoned it for the surer method of observation. The details which he has given, as the result of his researches, are exceedingly curious and instructive. He began by observing an ant-hill till he could perceive some change in its form. " The inhabitants," says he, " of that which I se- lected, kept within during the day, or only went out by subterranean galleries which opened at some feet distance in the meadow. There were, however, two or three small openings on the surface of the nest ; but I saw none of the labourers pass out this way, on account of their being too much exposed to the sun, which these in- sects greatly dread. This ant-hill, which had a round form, rose in the grass, at the border of a path, and had sustained no injury. I soon perceived that the freshness of the air and the dew invited the ants to walk over the surface of their nest ; they began making new apertures ; several ants might be seen arriving at the same time, thrusting their heads from the entrances, moving about their antennae, and at length adventuring forth to visit the environs. " This brought to my recollection a singular opinion of the ancients. They believed that ants were occupied IG ISSECT AKCHlTiiCTUKE. in their architectural labours during the night, when the moon was at its full." * M. Latrcille discovered a species of ants which were, so iar as he could ascertain, completely blind, f and of course it would be immaterial to them whether they worked by night or during the day. All observers in- deed agree that ants labour in the night, and a French naturalist is therefore of opinion that they never sleep, — a circumstance which is well ascertained with respect to other animals, such as the shark, which will track a ship in full sail for weeks together.:]: The ingenious his- torian of English ants, Gould, says they never intermit their labours by night or by day, except when compelled b}'^ excessive rains. It is probable the ancients were mis- taken in asserting that they only work when the moon shines ;§ for, like bees, they seem to find no difficulty in building in the dark, their subterranean apartments being as well finished as the upper stories of their buildings. But to proceed with the narrative of M. P. Huber. '* Having thus noticed the movements of these insects during the night, I found they were almost always abroad and engaged about the dome of their habitation alter sunset. This was directly the reverse of what I had observed in the conduct of the wood-ants (JP. Jttfa), who only go out during the day, and close their doors in the evening. The contrast was still more remarkable than I had previously supposed ; for upon visiting the brown ants some days after, during a gentle rain, 1 saw all their architectural talents in full pla^'. *' As soon as the rain commenced, they left in great numbers their subterranean residence, re-entered it al- most immediately, and then returned, bearing between * M. P. Huber on Ants, p. 23. ■\- Latreille, Hist. Nat. des FouimJs. I Dr. Clegliorn, Thesis de Somno. Aristotle, Hist. Animal, ix. 38. Pliny says, " Operantur et ijocfu plena luna ; eadem interlunio cessant," /. e. They work in the night at full moon, but they leave olT between moon and moon. It is the latter that we think doubtful. MAso^'-A^Ts. 17 their teeth pellets of earth, which they deposited on the roof of their nest. I could not at first conceive wliat this was meant for, but at length I saw little walls start up on all sides with spaces left between them. In seA'eral [Jaces, columns, ranged at regular distances, announced halls, lodges, and passages, which the ants proposed esta- blishing ; in a word, it was the rough beginning of a new story. " I watched with a considerable degree of interest the most trifling movements of my masons, and found they did not work after the manner of wasps and humble-bees, when occupied in constructing a covering to their nest. The latter sit, as it were, astride on the border or margin of the covering, and take it between their teeth to model and attenuate it according to their wish. The wax of which it is composed, and the paper which the wasp em- ploys, moistened by some kind of glue, are admirably adapted for this purpose, but the earth of which the ants make use, from its often possessing little tenacity, must be worked up after some other manner. " Each ant, then, carried between its teeth the pellet of earth it had formed by scraping with the end of its mandibles the bottom of its abode, a circumstance which I Jiave frequently witnessed in open day. This little mass of earth, being composed of particles but just united, could be readily kneaded and moulded as the ants wished ; thus, when they had applied it to the spot where they had to rest, they divided and pressed against it with their teeth, so as to till up the little inequalities of their wall. The antenna followed all their movements, passing over €ach particle of earth as soon as it was placed in its proper position. The whole was then rendered more compact by pressing it lightly with the fore-feet. This work went on remarkably fast. After having traced out the plan of their masonry, in laying here and there founda- tions for the pillars and partitions they were about to erect, they raised them gradually higher, by adding fresh materials. It often happened that two little walls, which were to form a gallery, were raised opposite, and at a B 3 18 INSECT ARCHITECTURE. slight distance from each other. When they had attained the height of four or five lines, the ants busied themselves in covering in the space left between them by a vaulted ceiling. *' As if they judged all their partitions of sufficient elevation, they then quitted their labours in the upper part of the building ; they affixed to the interior and upper part of each wall fragments of moistened earth, in an almost horizontal direction, and in such a way as to form a ledge, which, by extension, would be made to join that coming from the opposite wall. These ledges were about half a line in thickness ; and the breadth of the galleries was, for the most part, about a quarter of an inch. On one side several vertical partitions were seen to form the scaffolding of a lodge, which communi- cated with several corridors, by apertures formed in the masonry ; on another, a regularly-formed hall was con- structed, the vaulted ceiling of which was sustained by numerous pillars ; further off, again, might be recognised the rudiments of one of those cross roads of which I have before spoken, and in which several avenues terminate. These parts of the ant-hill were the most spacious ; the ants, however, did not appear embarrassed in constructing the ceiling to cover them in, although they were oft«n more than two inches in breadth. " In the upper part of the angles formed by the dif- ferent walls, they laid the first foundations of this ceil- ing, and from the top of each pillar, as from so many centres, a layer of earth, horizontal and slightly convex, was carried forward to meet the several portions coming from different points of the large public thoroughfare. " I sometimes, however, laboured under an apprehen- sion that the building could not possibly resist its own weight, and that such extensive ceilings, sustained only by a few pillars, would fall into ruin from the rain which continually dropped upon them ; but I was quickly con- vinced of their stability, from observing that the earth brought by these insects adhered at all points, on the slightest contact ; and that the rain, so far from lessening MASO>ii'-A>TS. 19 the cohesion of its particles, appeared even to increase it. Thus, instead of" injuring the building, it even con- tributed to render it still more secure. " These particles of moistened earth, which are only held together by juxtaposition, require a fall of rain to cement them more closely, and thus varnish over, as it were, those places where the walls and galleries remain uncovered. All inequalities in the masonry then disap- pear. The upper part of these stories, formed of several pieces brought together, presents but one single layer of compact earth. They require for their complete conso- lidation nothing but the heat of the sun. It sometimes, however, happens that a violent rain will destroy the apartments, especially should they be but slightly arched ; but under these circumstances the ants reconstruct them with wonderful patience. *' These different labours were can-ied on at the same time, and were so closely followed up in the different quarters, that the ant-hill received an additional story in the course of seven or eight hours. All the vaulted ceilings being formed upon a regular plan, and at equal distances from one wall to the other, constituted, when finished, but one single roof. Scarcely had the ants finished one story than they began to construct another ; but they had not time to finish it — the rain ceasing before the ceiling was fully completed. They still, however, continued their work for a few hours, taking advantage of the humidity of the earth ; but a keen north wind soon sprung up, and hastily dried the collected fragments, which, no longer possessing the same adherence, readily fell into powder. The ants, finding their eflbrts inef- fectual, were at length discouraged, and abandoned their employment ; but what was my astonishment when I saw them destroy all the apartments that were yet un- covered, scattering here and there over the last story the materials of which they had been composed ! These facts incontestably prove, that they employ neither gum, nor any kind of cement, to bind together the several substances of their nest ; but in place of this avail them 20 INSECT AECHITECTURE. selves of the rain, to work or knead the earth, leaving the sun and wind to dry and consolidate it." * Dr. Johnson of Bristol observed very similar proceed- ings in the case of a colony of red ants (JMyrmica rubra ?), the roof of whose nest was formed by a flat stone. Dur- ing dry weather, a portion of the side walls fell in ; but the rubbish was quickly removed, though no repairs were attempted till a shower of rain enabled them to work. As soon as this occurred, they worked with extraordinary rapidity, and in a short time the whole of the fallen parts were rebuilt, and rendered as smooth as if polished with a trowel. When a gardener wishes to water a plot of ground where he has sown seeds that require nice management, he dips a strong brush into water, and passes his hand backwards and forwards over the hairs for the purpose of producing a fine artificial shower. Huber success- fully adopted the same method to excite his ants to re- commence their labours, which had been interrupted lor want of moisture. But sometimes, when they deem it unadvisable to wait for rain, they dig down (as we re- marked to be the practice of the mason-bees) till they arrive at earth sufficiently moist for their purpose. They do not, however, like these bees, merely dig for mate- rials ; for they use the excavations for apartments, as well as what they construct with the materials thence derived. They appear, in short, to be no less skilful in mining than in building. Such is the general outline of the operations of this singular species ; but we are still more interested with the history which M. P. lluber hiis given of the labours of an individual ant. ''One rainy day," he says, " I observed a labourer of the dark ash-coloured species {Formica ft(sca) digging the ground near the aperture which gave entrance to the ant-hill. It placed in a heap the several fragments it had scraped up, and formed them into small pellets, v.hich it deposited here and there * M. P. Hubcr on Anfs, p. 31. MASON- AXTS. 21 upon the nest. It returned constantly to the same ])lace, and appeared to have a particular design, for it laboured with ardour and perseverance. I remarked a slight furrow, excavated in the ground in a straight line, re- presenting the plan of a path or gallery. The labourer (the whole of whose movements fell under my imme- diate observation) gave it greater depth and breadth, and cleared out its borders ; and I saw, at length — in which I could not be deceived — that it had the intention of establishing an avenue which was to lead from one of the stories to the underground chambers. This path, which was about two or three inches in length, and formed by a single ant, was opened above, and bordered on each side by a buttress of eai'th. Its concavity, in the form of a pij)e {gouttiere) , was of the most perfect regularity ; for the architect had not left an atom too much. The work of this ant was so well followed and understood, that I could almost to a certainty guess its next proceeding, and the very fragment it was about to remove. At the side of the opening where this path terminated was a second opening, to which it was neces- sary to arrive by some road. The same ant began and finished this undertaking without assistance. It furrowed out and opened another path, parallel to the first, leaving between each a little wall of three or four lines in height." Like the hive-bees, ants do not seem to work in con- cert, but each individual separately. There is, conse- quently, an occasional want of coincidence in the walls and arches ; but this does not much embarrass them, ior A worker, on discovering an error of this kind, seems to know how to rectify it, as appears from the following- observations : — "A wall," says M. Huber, *' had been erected, with the view of sustaining a vaulted ceiling, still incomplete, that had been projected towards the wall of the opposite chamber. The workman who began constructing it, had given it too little elevation to meet the opposite parti- tion, upon which it was to rest. Had it been continued on the original plan, it must infallibly have met the wall at about one half of its height ; and this it was necessary 22 INSECT ARCHITECTURE. to avoid. This state of things very forcibly claimed my attention ; when one of the ants arriving at the place, and visiting the works, appeared to be struck by the dif- ficulty which presented itself; but this it as soon ob- viated, by taking down the ceiling, and raising the wall upon which it reposed. It then, in my presence, con- structed a new ceiling with the fragments of the former one. *' When the ants commence any undertaking, one would suppose that they worked after some preconceived idea, which, indeed, would seem verified by the execu- tion. Thus, should any ant discover upon the nest two stalks of plants which lie crossways, a disposition favour- able to the construction of a lodge, or some little beams that may be useful in forming its angles and sides, it examines the several parts with attention ; then distri- butes, with much sagacity and address, parcels of earth in the spaces, and along the stems, taking from every quarter materials adapted to its object, sometimes not caring to destroy the work that others had commenced ; so much are its motions regulated by the idea it has con- ceived, and upon which it acts, with little attention to all else around it. It goes and returns, until the plan is sufficiently understood by its companions. " In another part of the same ant-hill," continues M, Huber, "several fragments of straw seemed expressly placed to form the roof of a large house ; a workman took advantage of this disposition. These fragments lying horizontally, at half an inch distance from the ground, formed, in crossing each other, an oblong paral- lelogram. The industrious insect commenced by placing earth in the several angles of this frame- work, and all along the little beams of which it was composed. The same workman afterwards placed several rows of the same materials against each other, when the roof became very distinct. On perceiving the possibility of profiting by another plant to support a vertical wall, it began laying the foundations of it ; other ants having by this time arrived, finished in common what this had commenced."* * Huber on Ants, p. 43. MASOK-ANTS. 2a M. Hubermade most of his observations upon the' pro- cesses followed by ants in glazed artificial hives or formi- caries. The preceding- figure represents a view of one of his formicaries of mason-ants. We have ourselves followed up his observations, both on natural ant-hills and in artificial formicaries. On dig- ging cautiously into a natural ant-hill, established upon the edge of a garden walk, we were enabled to obtain a pretty complete view of the interior structure. There were two stories, composed of large chambers, irregularly oval, communicating with each other by arched galleries, the walls of all w^iich w'ere as smooth and well polished as if they had been passed over by a plasterer's [trowel. The floors of the chambers, we remarked, were by no means either horizontal or level, but all more orlless sloped, and exhibiting in each chamber at least two slight 24 ISSECT ARCHITECTURE. depressions of an irregular shape. We left the under story of this nest untouched, with the notion that the ants might repair the upper galleries, of which we had made a vertical section ; but instead of doing so they migrated during the day to a large crack formed by the dryness of the weather, about a yard from their old nest. (J. R.) ^\e pi!t a number of yellow ants {Formica Jiava), with their eggs and cocoons, into a small glass frame, more than half full of moist sand taken from their native hill, and placed in a sloping position, in order to see whether they would bring the nearly vertical, and there- fore insecure, portion to a level by masonry. We were delighted to perceive that they immediately resolved ni[)on performing the task which had been assigned them, though they did not proceed very methodically in their manner of building ; for instead of beginning at the bot- .ix)m and building upwards, many of them went on to add to the top of the outer surface, which increased rather than diminished the security of the whole. Withal, however, they seemed to know how far to go, for no portion of the newly-built wall fell ; and in two days they had not only reared a pyramidal mound to prop the rest, but had constructed several galleries and chambers for lodging the cocoons, which we had scattered at ran- dom amongst the sand. The new portion of this build- ing is represented in the figure as supporting the upper and insecure parts of the nest. MASON-AKTS. 25 We are soiry to record that our ingenious little masons were found upon the third day strewed about the outside of the building dead or dying, either from over fatigue or perhaps from surfeit, as we had supplied them v, ith as much honey as they could devour. A small colony of turf-ants have at this moment (July 28th, 1829) taken possession of the premises of their own accord. (J. IX.) 26 INSECT ARCHITIXTURE. CHAPTER XV. Structures of the Wood-Ant or Pismire, and of Carpenter- Ants. The largest of our British ants is that called the Hill- ant by Gould, the Fallow-ant by the English translator of Huber, and popularly the Pismire ; but which we think may be more appropriately named the Wood-ant {Formica rufa, Latr,), from its invariable habit of living in or near woods and forests. This insect may be readily distinguished from other ants by the dusky black colour of its head and hinder parts, and the rusty brown of its middle. The structures reared by this species are often of considerable magnitude, and bear no small resemblance to a rook's nest thrown upon the ground bottom up- wards. They occur in abundance in the woods near London, and in many other parts of the country : in Oak of Honour wood alone, we are acquainted with the localities of at least two dozen, — some in the interior and others on the hedge-banks on the outskirts of the wood. (J. R.) The exterior of the nest is composed of almost every transportable material which the colonists can find in their vicinity : but the greater portion consists of the stems of withered grass and short twigs of trees, piled up in apparent confusion, but with sufficient regularity to render the whole smooth, conical, and sloping towards the base, for the purpose, we may infer, of carrying oft" rain water. When within reach of a corn-field, they often also pick up grains of wheat, barley, or oats, and carry them to the nest as building materials, and not for food, as was believed by the ancients. There are won- ders enough observable in the economy of ants, without "WOOD-ANTS. 27 having" recourse to fancy — wonders which made Aristotle extol the sagacity of bloodless animals, and Cicero ascribe to them not only sensation, but mind, reason, and memory.* jJElian, however, describes, as if he had actually witnessed it, the ants ascending a stalk of grow- ing corn, and throwing down " the eai's which they bit oft" to their companions below." Aldrovand assures us that he had seen their granaries ; and others pretend that they shrewdly bite oft' the ends of the grain to pre- vent it from germinating. t These are fables which accurate observation has satisfactorily contradicted. But these errors, as it frequently happens, have con- tributed to a mo]"e perfect knowledge of the insects than we might otherwise have obtained ; for it was the wish to prove or disprove the circumstance of their storing up and feeding upon grain, which led Gould to make his observations on English ants ; as the notion of insects being produced y>"om putrid carcases had before led Redi to his ingenious experiments on their generation. Yet, although it is more than eighty years since Gould's book was published, we find the error still repeated in verj' respectable publications 4 The coping which we above described as forming the exterior of the wood-ant's nest, is only a small portion of the structure, which consists of a great number of interior chambers and galleries, with funnel-shaped avenues leading to them. The coping, indeed, is one of the most essential parts, and we cannot follow a more de- lightful guide than the younger Huber in detailing its formation. " The labourers," he says, '* of which the colony is composed, not only work continually on the outside of their nest, but, differing very essentially from other species, who willingly remain in the interior, sheltered * In formica non modo sensus, sed etiam mens, ratio, me- moria. f Aldrovand us de Formicis, and Johnston, Thaumaturg. Nat. p. 356. X See Professor Paxton's lUustr. of Scripture, i. 307. 28 INSECT ARCHITKCTURE. from the sun, they prefer living in the open air, and do not hesitate to cany on, even in our presence, the greater part of their operations. " To have an idea how the straw or stubble-roof is formed, let us take a view of the ant-hill at its origin, when it is simply a cavity in the earth. Some of its future inhabitants are seen wandering about in search of materials fit for the exterior work, with which, though rather irregularly, they cover up the entrance ; whilst others are employed in mixing the earth, thrown up in hollowing the interior, with fragments of wood and leaves, which are every moment brought in by their fel- low-assistants ; and this gives a certain consistence to the edifice, which increases in size daily. Our little architects leave here and there cavities, where they in- tend constructing the galleries which are to lead to the exterior, and as they remove in the morning the barriers placed at the entrance of their nest the preceding even- ing, the passages are kept open during the whole time of its construction. We soon observed the roof to be- come convex ; but we should be greatly deceived did we consider it solid. This roof is destined to include many apartments or stories. Having observed the motions of these little builders through a pane of glass, adjusted against one of their habitations, I am thence enabled to speak with some degree of certainty upon the manner in which they are constructed. I ascertained that it is by excavating, or mining the under portion of their edi- fice, that they Ibrm their spacious halls, low indeed, and of heavy construction, yet sufiiiciently convenient for the use to which they are appropriated, that of receiving, at certain hours of the day, the larvae and pupae. " These halls have a free conmmnication by galleries, made in the same manner. If the materials of which the ant-hill is composed were only interlaced, they would fall into a confused heap every time the ants attempted to bring them into regular order. This, however, is obviated by their tempering the earth with rain-water, which, afterwards liardened in the sun, so completely and effectually binds together the several substances, as WOOD-ANTS. 29 to permit the removal of certain fragments from the ant- hill without any injury to the rest ; it, moreover, strongly opposes the introduction of the rain. I never found, even after long and violent rains, the interior of the nest ■vvetted to more than a quarter of an inch from the sur- face, provided it had not been previously out of repair, or deserted by its inhabitants. " The ants are extremely well sheltered in their chambers, the largest of which is placed nearly in the centre of the building ; it is much loftier than the rest, and traversed only by the beams that support the ceiling ; it is in this spot that all the galleries terminate, and this forms, for the most part, their usual residence. " As to the luiderground portion, it can only be seen when the ant-hill is placed against a declivity ; all the interior may be then readily brought in view, by simply raising up the straw roof. The subterranean residence consists of a range of apartments, excavated in the earth, taking an horizontal direction."* M. P. Huber, in order to observe the operations of the wood-ant with more attention, transferred colonies of them to his artificial formicaries, plunging the feet of the stand into water to prevent their escape till they M'cre reconciled to their abode, and had made some progress in repairing it. On the next page is a figure of the apparatus which he used for this purpose. There is this remarkable difference in the nest of the wood-ants, that they do not construct a long covert way as if for concealment, as the yellow and the brown ants do. The wood-ants are not, like them, afraid of being sur- prised by enemies, at least during the day, when the whole colony is either foraging in the vicinity or em- ployed on the exterior. But the proceedings of the wood-ants at night are well worthy of notice ; and when M. Huber began to study their economy, he directed his entire attention to their night proceedings. '^ I re- marked," says he, " that their habitations" changed in appearance hourly, and that the diameter of those * Kuber on Ants, p. 15. 30 INSECT ARCHITECTURE. spacious avenues, where so many ants could freely pass each other during the day, was, as night approached, gradually lessened. The aperture, at length, totally dis- appeared, the dome was closed on all sides, and the ants retired to the bottom of their nest. " In further noticing the apertures of these ant-hills, I fully ascertained the nature of the labour of its inhabit- ants, of which I could not before even guess the purport ; for the surface of the nest presented such a constant scene of agitation, and so many insects were occupied in carrying materials in every direction, that the movement offered no other image than that of confusion. " I saw then clearly that they were engaged in stop- ping up passages; and, for this purpose, they at first brought forward little pieces of wood, which they de- posited near the enfrance of those avenues they wished to close ; they placed them in the stubble ; they then went to seek other twigs and fragments of wood, which WOOJD-A>TS. 31 they disposed above the first, but in a different direction, and appeared to choose pieces of less size in proportion as the work advanced. They, at length, brought in a number of dried leaves, and other materials of an enlarged form, with which they covered thereof: an exact minia- ture of the art of our builders, when they form the co- vering of any building? Natuie, indeed, seems every- where to have anticipated the inventions of which we boast, and this is doubtless one of the most simple. " Our little insects, now in safety in their nest, retire gradually to the interior before the last passages are closed ; one or two only remain without, or concealed ))ehind the doors on guard, while the rest either take their repose, or engage in different occupations in the most perfect security. I was impatient to know what took place in the morning upon these ant-hills, and therefore visited them at an early hour. I found them in the same state in which I had left them the preceding evening. A few ants were wandering about on the sur- face of the nest, some others issued from time to time from under the margin of their little roofs formed at the entrance of the galleries : others afterwards came forth, who began removing the wooden bars that blockaded the entrance, in which they readily succeeded. This labour occupied them several hours. The passages were at length free, and the materials with which they had been closed scattered here and there over the ant-hill. Every day, morning and evening, during the fine wea- ther, I was a witness to similar proceedings. On days of rain the doors of all the ant-hills remained closed. When the sky was cloudy in the morning, or rain was indicated, the ants, who seemed to be aware of it, opened but in part their several avenues, and immediately closed them when the rain commenced." * The galleries and chambers which are roofed in as thus described, are very similar to those of the mason- ants, being partly excavated in the earth, and partly built with the clay thence procured. It is in these they * Huber on Ants, p. 11, 32 INSECT ARCHITECTUKE. pass the night, and also the colder months of the winter, when they become torpid, or nearly so, and of course re- quire not the winter granaries of com with which the ancients fabulously furnished them. Cakpenter-Axts. The ants that work in wood perform much more exten- sive operations than any of the other carpenter insects which we have mentioned. Their only tools, like those of bees and wasps, are their jaws or mandibles ; but though these may not appear so curiously constructed as the ovipositor file of the tree-hopper (Cicada), or the rasp and saw of the saM-flies {Tentliredimdce), they are no less efficient in the performance of what is required. Among the carpenter-ants the emmet or jet-ant {¥. fiOiginosd) holds the first rank, and is easily known by being rather less in size than the wood-ant, and by its fine shining black colour. It is less common in Britain than some of the preceding, though its colonies may occasionally be met with in the trunks of decaying oak or willow trees in hedges. " The labourers,'' says Huber, " of this species work always in the interior of trees, and are desirous of being screened from observation : thus every hope on our part is precluded of following them in their several occupa- tions. I tried every expedient I could devise to sur- mount this difficulty ; I endeavoured to accustom these ants to live and work under my inspection, but all my efforts were unsuccessful ; they even abandoned the most considerable portion of their nest to seek some new asylum, and spurned the honey and sugar which I ofi'ered them for nourishment. I was now, by necessity, limited to the inspection only of their edifices ; but, by decom- posing some of the fragments with care, I hoped to ac- quire some knowledge of their organization. " On one side I found horizontal galleries, hidden in great part by their walls, which follow the circular di- rection of the layers of the wood ; and on another, pa- rallel galleries, separated by extremely thin partitions, having no communication except by a few oval apertures. CARPENTER-ANTS. 33 Such is the nature of these works, remarkable for their delicacy and lightness. " In other fragments I found avenues which opened laterally, including portions of walls and transverse par- titions, erected here and there within the galleries, so as to form separate chambers. When the work is further advanced, round holes are always observed, encased, as it were, between two pillars cut out in the same wall. These holes in course of time become square, and the pillars, originally arched at both ends, are worked into regular columns by the chisel of our sculptors. This, then, is the second specimen of their art. This portion of the edifice will probably remain in this state. " But in another quarter are fragments differently wrought, in which these same partitions, pierced now in every part, and hewn skilfully, are transformed into co- lonnades, which sustain the upper stories, and leave a free communication throughout the whole extent. It can readily be conceived how parallel galleries, hollowed out upon the same plan, and the sides taken down, leaving only from space to space what is necessary to sustain their ceilings, may form an entire story ; but as each has been pierced separately, the flooring cannot be very level : this, however, the ants turn to their advantage, since these furrows are better adapted to retain the larvae that may be placed there. " The stories constructed in the great roots offer greater irregularity than those in the very body of the tree, arising either from the hardness and interlacing of the fibres, which renders the labour more difficult, and obliges the labourers to depart from their accustomed manner, or from their not observing in the extremities of their edifice the same arrangement as in the centre ; whatever it be, horizontal stories and numerous partitions are still found. If the work be less regular, it becomes more delicate ; for the ants, profiting by the hardness and solidity of the materials, give to their building an extreme degree of lightness. I have seen fragments of from eight to ten inches in length, and of equal height, formed of wood as thin as paper, containing a number of VOL,. II. c 9A- IKSECr AF.cn ITJiCrURE, Portion of a Tree, with Clianibers and Galleries diistled out by Jet- Ants. nparimcuts, and presenting a most singular appearance. At tlie entrance of these apartments, worked out with so much care, are very considerable openings ; but in j)laco of chambers and extensive galleries, the layers of the wood are hewn in arcades, allowing the ants a free passage in every direction. Tiiese may be regarded as the gates or vestibules conducting to the several lodges." * It is a singular circumstance in the structures of these ants, that all the wood which they carve is tinged of a black colour, as if it were smoked ; and M, Huber was not a little solicitous to discover whence this arose. It certainly does not add to the beauty of their streets, which look as sombre as the most smoke-dyed walls in ihe older lanes of the metropolis. M. Huber could not satisfy himself whether it was caused by the exposure of the wood to the atmosphere, by some emanation from the ants, or by the thin layers of wood being acted upon or decomposed by the formic acid.f But if any or all of tliese causes operated in blackening the wood, wo should be ready to anticipate a similar effect in the case Kuber, p. 5G. f The acid of ants. CARPEXTER-A^TS. 35 of Other species of ants which inhabit trees ; yet the black tint is only found in the excavations of the jet-ant. We are acquainted with several colonies of the jet- ants, — one of which, in the roots and trunk of an oak on the road i'roni Lewisham to Sydenham, near Brockley, in Kent, is so extremely populous, that the numbers of its inhabitants appeared to us beyond any reasonable estimate. None of the other colonies of this species which v.e have seen appear to contain many hundreds. On cutting into the root of the before-mentioned tree, we found the vertical excavations of nmch larger dimen- sions, both in width and depth, than those represented by Iluber in the preceding cut (page 34). What sur- prised us the most was to see the tree growing vigor- ously and fresh, though its roots were chiseled in all directions by legions of workers, while every leaf, and every inch of the bark, was also crowded by parties of foragers. On one of the low branches we found a de- serted nest of the white-throat {Si/lvia cinerea, Tem- mixck), in the cavity of which they were piled upon one another as close as the unhappy negroes in the hold of a slave-ship ; but we could not discover what had attracted them hither. Another dense group, collected on one of the branches, led us to the discovery of a very- singular oak gall, formed on the bark in the shape of a pointed cone, and crowded together. It is probable that the juice which they extracted from these galls was much to their taste. (J. R.) Beside the jet-ant, several other species exercise the art of carpentry, — nay, what is more wonderful still, they have the ingenuity to knead up, with spiders'-web ior a cement, the chips which they chisel out into u material with which they construct entire chambers. The species which exercise this singular art are the Ethiopian (^Formica nigra) and the yellow ant (P. jlava)* Wo once observed the dusky ants (2^. fused), at Biackheath, in Kent, busily employed in carrying out * Huber. c 2 36 INSECT ARCHITECTURE. chips from the interior of a decaying black poplar, at the root of which a colony was established ; but, though it thence appears that this species can chisel wood if they choose, yet they usually burrow in the earth, and by preference, as we have remarked, at the root of a tree, the leaves of which supply them with food. Among the foreign ants we may mention a small yellow ant of South America, described by Dampier, which seems, from his account, to construct a nest of green leaves. '' Their sting," he says, " is like a spark of fire ; and they are so thick among the boughs in some places, that one shall be covered with them before he is aware. These creatures have nests on great trees, placed on the body between the limbs : some of their nests are as big as a hogshead. This is their winter habitation ; for in the wet season they all repair to these their cities, where they preserve their eggs. In the dry season, when they leave their nests, they swarm all over the woodlands, for they never trouble the savannahs. Great paths, three or four inches broad, made by them, may be seen in the woods. They go out light, but bring home heavy loads on their backs, all of the same sub- stance, and equal in size. I never observed anything besides pieces of green leaves, so big that I could scarcely see the insect for his burthen ; yet they would march stoutly, and so many were pressing forward that it was a very pretty sight, tor the path looked perfectly green with them." Ants observed in New South Wales, by the gentlemen in the expedition under Captain Cook, are still more in- teresting. "Some," we are told, "are as green as a leaf, and live upon trees, where they build their nests of various sizes, between that of a man's head and his fist. These nests are of a very curious structure : they are formed by bending down several of the leaves, each of which is as broad as a man's hand, and gluing the points of them together, so as to form a purse. The viscous matter used for this purpose is an animal juice CARPENTER-ANTS. 37 which jiature has enabled them to elaborate. Their method of first bending down the leaves we had no opportunity to observe ; but we saw thousands uniting all their strength to hold them in this position, while other busy multitudes were employed within in applying this gluten that was to prevent their returning back. To satisfy ourselves that the leaves were bent and held down by the efforts of these diminutive artificers, we disturbed them in their work ; and as soon as they were driven from their stations, the leaves on which they were em- ployed sprang up with a force much,' greater than we could have thought them able to conquer by any com- bination of their strength. But, though we gratified our curiosity at their expense, the injury did not go un- revenged ; for thousands immediately threw themselves upon us, and gave us intolerable pain Mith their stings, especially those which took possession of our necks and hair, from whence they were not easily driven. Their sting was scarcely less painful than that of a bee ; but, except it was repeated, the pain did not last more than a minute. " Another sort are quite black, and their operation and manner of life are not less extraordinary. Their habitations are the inside of the branches of a tree, which they contrive to excavate by working out the pith almost to the extremity of the slenderest twig, the tree at the same time flourishing as if it had no such inmate. When we first found the tree we gathered some of the branches ; and were scarcely less astonished than we should have been to find that we had profaned a consecrated grove, where every tree, upon being wounded, gave signs of life ; for we were instantly covered with legions of these animals, swarming from every broken bough, and inflicting their stings with incessant violence. " A third kind we found nested in the root of a plant, which grows on the bark of trees in the manner of mistletoe, and which they had perforated for that use. This root* is commonly as big as a large turnip, and sometimes much bigger. When we cut it, we found it intersected by innumerable winding passages, all filled 38 I>SJi:CT ARCHITECTURE. with these animals, by which, however, the vegetation of the plant did not appear to have suffered any injury. We never cut one of these roots that was not inhabited, though some were not bigger than a hazel-nut. The animals themselves are very small, not more than half as big as the common 'red ant in England. They had •Slings, but scarcely force enough to make them felt : they had, however, a power of tormenting us in an equal, if not in a greater degree ; for the moment we handled the root, they swarmed from innumerable holes, and running about those parts of the body that were un- covered, produced a titillation more intolerable than pain, except it is increased to great violence." * The species called sugar-ants in the West Indies are particularly destructive to the sugar-cane, as well as to lime, lemon, and orange-trees, by excavating their nests at the roots, and so loosening the earth that they are frequented uprooted and blown down by the winds. If this does not happen, the roots are deprived of due nou- rishment, and the plants become sickly and die.f * Hawkeswortirs Account of Cook's First VoyagR. t Phil. Trans., xxx., p. ?A(j. WHITE ANTS. CIIAPTErx XVI. Structures of Wliite Ants, or Termites. WiiEX wc look back upon the details which wo have -given of the industry and ingenuity of numerous tribes of insects, both solitary and social, we are induced to think it almost impossible that they could be surpassed. The structures of wasps and bees, and still more those of the wood-ant (^Formica nifa), when placed in comparison with the size of the insects, equal our largest cities com- pared with the stature of man. But when we look at the buildings erected by the white ants of troj)ical climates, all that we have been surveying dwindles into insignificance. Their industry appears greatly to sur- pass that of our ants and bees, and they are certainly more skilful in architectural contrivances. The elevci- tion, also, of their edifices is more than five hundred times the height of the builders. Were our houses built according to the same proportions, they would be tv.clve or fifteen times higher than the London Monument, and four or five times higher than the pyramids of Egypt, with corresponding dimensions in the basements of the edifices. These statements are, perhaps, necessary to impress the extraordinary labours of ants upon the mind ; for we are all more or less sensible to the force of com- parisons. The analogies between the works of insects and of men are not perfect ; for insects are all provided with instruments peculiarly adapted to tJie end which they instinctively seek, while man has to form a plan by progressive thought and upon the experience of others, and to complete it with tools which he also invents. The termites do not stand above a quarter of an inch high, while their nests are frequently twelve feet; and .40 INSECT ARCHITECTURE, Jobson mentions some which he had seen as high as twenty feet; "of compass," he adds, "to contain a dozen men, with the heat of the sun baked into that hardness, that we used to hide ourselves in the ragged tops of them when we took up stands to shoot at deer or wild beasts."* Bishop Ileber saw a number of these high ant-hills in India, near the principal entrance of the Sooty or Moorshedabad river. " Many of them," he says, " were five or six feet high, and probably seven or eight feet in circumference at the base, partially over- grown with grass and ivy, and looking at a distance like the stumps of decayed trees. I think it is Ctesias, among the Greek writers, who gives an account alluded to by Lucian, in his ' Cock,' of monstrous ants in India, as large as foxes. The falsehood probably originated in the stupendous fabrics which they rear here, and which certainly might be supposed to be the work of a much larger animal than their real architect."! Herodotus has a similar fable of the enormous size and brilliant ap- pearance of the ants of India. Nor is it only in constructing dwellings for themselves that the termites of Africa and of other hot climates employ their masonic skill. Though, like our ants and wasps, they are almost omnivorous, yet wood, particu- larly when felled and dry, seems their favourite article of food ; but they have an utter aversion to feeding in the light, and always eat their way with all expedition into the interior. It thence would seem necessary for them either to leave the bark of a tree, or the outer por- tion of the beam or door of a house, undevoured, or to eat in open day. They do neither; but are at the trouble of constructing galleries of clay, in which they can conceal themselves, and feed in security. In all their foraging excursions, indeed, they build covert ways, by which they can go out and return to their encamp- ment. J * Jobson's Gambia, in Piirclias's Pilgrim, ii. p. 1570. f Hebei's Journal, vol. i. p. 248. I Smeatbmaii, in Pliil. Traiis., vol. Ixxi. ^V111TE A>TS. 41 Others of the species (for there are several), instead of building galleries, exercise the art of miners, and make their approaches under ground, penetrating beneath the foundation of houses or areas, and rising again either through the floors, or by entering the bottom of the posts that support the building, when they follow the course of the fibres, and make their way to the top, boring holes and cavities in different places, as they proceed. Multitudes enter the roof, and intersect it with pipes or galleries, formed of wet clay ; which serve for passages in all directions, and enable them more readily to fix their habitations in it. They prefer the softer woods, such as pine and fir, which they hollow out with such nicety, that they leave the surface whole, after having eaten away the inside, A shelf or plank attacked in this manner, looks solid to the eye, when, if weighed, it will not out-balance two sheets of pasteboard of the same dimensions. It sometimes happens that they carry this operation so far on stakes in the open air, as to render the bark too flexible for their purpose ; when they remedy the defect by plastering the whole stick with a sort of mortar which they make with clay ; so that, on being struck, the form vanishes, and the artificial covering falls in fragments on the ground. In •the woods, when a large tree falls from age or accident, they enter it on the side next the ground, and devour it at leisure, till little more than the bark is left. But in tliis case they take no precaution of strengthening the outward defence, but leave it in such a state as to deceive an eye unaccustomed to see trees thus gutted of their insides; and " you may as well," says Mr. Smeathman, "step upon a cloud." It is an extraordinary fact, that w^hen these creatures have formed pipes in the roof of a house, instinct directs them to prevent its fall, which would ensue from their having sa})ped the posts on which it rests ; but as they gnaw away the wood, they fill up the interstices with clay, tempered to a surprising de- gree of hardness ; so that, w hen the house is pulled down, these posts are transformed from wood to stone. They make the walls of their galleries of the same com- c 3 42 INSECT ARCHITECTURE. position as their nests, varying the material saccording to their kind : one species using red clay, another black clay, and a third a woody substance, cemented with gums, as a security from the attacks of their enemies, particularly the common ant, which, being defended by u strong, horny shell, is more than a match for them ; and when it can get at them, rapaciously seizes them, and drags them to its nest for food for its young brood. If any accident breaks down part of their walls, they repair the breach Mith all speed. Instinct guides them to perform their office in the creation, by mostly confin- ing their attacks to trees that are beginning to decay, or such timber as has been severed from its root for use, and would decay in time. Vigorous, healthy trees do not require to be destroyed, and, accordingly, these con- sumers have no taste for them.* M. Adanson describes the termites of Senegal as con- structing covert \Miys along the surface of wood which they intend to attack : but though we have no reason to distrust so excellent a naturalist, in describing what he saw, it is certain that they more commonly eat their wa^- into the interior of the wood, and afterwards form the galleries, when they find that they have destroyed the Vv'ood till it will no longer aftbrd them protection. lint it is time that we should come to their principal* building, which may, with some propriety, be called a city ; and, according to the method we have followed in other instances, we shall trace their labours fi-om the commencement. We shall begin Vtith the operations of the sj)ecies which may be appropriately termed the Warrior {lennesfaialis, Link. ; 2\ bell/cosv.s, Smeatii.) We must premise, that though they have been termed white atits, they do not belong to the same order of in- sects with our ants ; yet they have a slight resemblance to ants in their ibrm, but more in their economy, fsmeathman, to v.hom we owe our chief knowledge of the genus, describes them as consisting of kings, queens, soldiers, and workers, and is of o}»inion that the workers * Sincathmai!. WHITE ANTS. 43 Termesbollicosus in the x^ingcd state. nre larvge, the soldiei's nyniphae, and the kings and queens the perfect insects. In this opinion he coincides with Sparrmann* and others; but Latreille is inchned to think, from what he observed in a European species (^Tcnnes lucifvgits) , found near Bordeaux, that the sokliers form a distinct race, Hke the neuter workers amono^ bees and ants, while the working termites are h\rv8e,t which are furnished with strong mandibles for jrnawing ; when they become nymphs, the rudiments of iour wings appear, which are fully developed in the perfect insects. In this state, they migrate to form new colonies, but the greater number of them perish in a few hours, or become the prey of birds, and even the natives, who fry them as delicacies. " I have discoursed with several gentlemen," says Smeathman, "upon the taste of the white ants, and on comparing notes, we have always agreed that they are most delicious and delicate eating. One gentleman compared them to sugared mar- row, another to sugared cream and a paste of sweet almonds."! jNIr. Smeathman's very interesting paper affords us the most authentic materials for the further description of these wonderful insects ; and we therefore continue partly to extract from, and partly to abridge, his account. * Quoted by De Geer, vol. vii. f Hist. Nat. Generale, vol. xiii. p. 66. I Smeathman, in Phil. Trans, vol. Ixxi. p. 169, note. 44 INSECT ABCHITECTURB. The few pairs that are so fortunate as to survive the various casualties that assail them, are usually found by workers (larvae), which, at this season, are running con- tinually on the surface of the ground, on the watch for them. As soon as they discover the objects of their search, they begin to protect them from their surround- ing enemies, by inclosing them in a small chamber of clay, where they become the parents of a new com- munity, and are distinguished from the other inhabitants of the nest, by the title of king and queen. Instinct directs the attention of these labouring insects to the preservation of their race, in the protection of this pair and their offspring. The chamber that forms the rudi- ment of a new nest is contrived for their safety, but the entrances to it are too small to admit of their ever leav- ing it ; consequently, the charge of the eggs devolves upon the labourers, who construct nurseries for their re- ception. These are small, irregularly-shaped chambers, placed at first round the apartment of the king and queen, and not exceeding the size of a hazel-nut ; but in nests of long standing they are of great comparative magni- tude, and distributed at a greater distance. The recep- tacles for hatching the young are all composed of wooden materials, apparently joined together with gum, and, by way of defence, cased with clay. The chamber that contains the king and queen is nearly on a level with the surface of the ground ; and as the other apartments are formed about it, it is generally situated at an equal dis- tance from the sides of the nest, and directly beneath its conical point. Those apartments which consist of nurseries and magazines of provisions, form an intricate labyrinth, being separated by small, empty chambers and galleries, which surround them, or afford a communica- tion from one to another. This labyrinth extends on all sides to the outward shells, and reaches up within it to two-thirds or more of its height, leaving an open area above, in the middle, under the dome, which reminds the spectator of the nave of an old cathedral. Around this are raised three or four large arches, which are sometimes two or three feet high, next the front of the area, but WHITE ANTS. 45 diminish as they recede further back, and are lost amidst the innumerable chambers and nurseries behind them. Every one of these buildings consists of two distinct parts, the exterior and the interior. The exterior is one large shell, in the manner of a dome, large and strong enough to inclose and shelter the interior from the vicis- situdes of the weather, and the inhabitants from the attacks of natural or accidental enemies. It is always, therefore, much stronger than the interior building, which is the habitable part, divided, with a wonderful kind of regularity and contrivance, into an amazing number of apartments for the residence of the king and queen, and the nursing of the numerous progeny ; or for magazines, which are always found well filled with stores and provisions. The hills make their first appearance above ground by a little turret or two, in the shape of sugar-loaves, which are run a foot high or more. Soon after, at some little distance, while the former are in- creasing in height and size, they raise others, and so go on increasing their number, and widening them at the base, till their works below are covered with these tur- rets, of which they always raise the highest and largest in the middle, and, by filling up the intervals between each turret, collect them into one dome. They are not very curious or exact in the workmanship, except in making them very solid and strong; and when, by their joining them, the dome is completed, for which purpose the turrets answer as scaffolds, they take away the middle ones entirely, except the tops, which, joined together, make the crown of the cupola, and apply the clay to the building of the works within, or to erecting fresh turrets for the purpose of raising the hillock still higher ; so that some part of the clay is probably used several times, like the boards and posts of a mason's scalibids. When these hills are little more than half their height, it is a common practice of the wild bulls to stand as sentinels on them, while the rest of the herd are ruminat- ing below. They are sufticiently strong for that purpose ; and at their full height, answer excellently well as places of look-out; and jNIr. Sraeathman has been, .with four 46 IXSXCT ARCHITECTLRE. aiore, on the top of one of these hillocks, to watch for a vessel in sight. The outward shell, or dome, is not only of use to protect and support the interior buildings from external violence and the heavy rains, but to collect and preserve a regular degree of the warmth and moisture necessary for hatching the eggs and cherishing the young. The royal chamber occupied by the king and queen appears to be, in the opinion of this little people, of the most consequence, being always situated as near the centre of the interior building as possible. It is always nearly in the shape of half an egg, or an obtuse oval, within, and may be supposed to represent a long oven. In the infant state of the colony, it is but about an inch in length ; but in time will be increased to six or eight inches, or more, in the clear, being always in ])ro- portion to the size of the queen, who, increasing in bulk as 1:1 age, at length requires a chamber of such dimensions. Queon distended with Eggs, Its floor is perfectly horizontal, and, in large hillocks, sometimes more than an inch thick of solid clay. The, roof, also, which is one solid and well-turned oval arch, is generally of about the same solidity, but in some places it is not a quarter of an inch thick, on the sides where it joins the floor, and where the doors or en- trances are made level with it, at nearly equal distances from each other. These entrances will not admit any animal larger than the soldiers or labourers ; so that the king and the queen (who is, at full size, a thousand times the weight of a king) can never possibly go out, but remain close prisoners. The royal chamber, if in a large hillock, is surrounded •\vuiTr ANTS. 47 ))y a countless number of others, of different sizes, shape;?^ luid dimensions ; but all of them arehed in one way or another — sometimes elliptical or oval. These either open into each other, cr communicate by passages as wide as, and are evidently made for, the soldiers and attend- ants, of w horn great numbers are necessary, and always in waiting. These apartments are joined by the maga- zines and nurseries. The Ibrm.er are chambers of cla}^, and are always well fdled with provisions, which, to the naked eye, seem to consist of the raspings of wood, and plants which the termites destroy ; but are found by the microscope to be principally the gums or inspissated juices of plants. These are thrown together in little masses, some of which are finer than others, and resemble the sugar about ])reserved fruits ; others are like tears of gum, one quite transparent, another like amber, a third brown, and a fourth quite o])aque, as we see often in ]);ircels of ordinary gums. These magazines are inter- mixed with the nurseries, which are buildings totally ditlerent from the rest of the apartments ; lor these are composed entirely of wooden materials, seemingly joined together with gums. Mr. Smeathman calls them the nurseries, because they are invariably occupied by the eggs and young ones, which appear at first in the shape of labourers, but white as snow. These buildings are cxceedingl}' compact, and divided into many very small irregular-shaped chambers, not one of which is to be ibund of half an inch in width. They are placed all round, and as near as possible to the royal apartments. AVhen the nest is in the infant state, the nurseries are close to the royal chambers ; but as, in j^rocess of time, the queen enlarges, it is necessary to enlarge the chamber for her accommodation ; and as she then lays a greater number of eggs, and requires a greater number of at- tendants, so it is necessary to enlarge and increase the number of the adjacent apartments ; for which purpose the small nurseries which are first built are taken to })ieces, rebuilt a little further of a size larger, and the number of them increased at the same time. Thus they continually enlarge their a])avtmcnts, pull down, rcjiaii', 48 INSECT ARCHITECTURE. or rebuild, according to their wants, with a degree of sagacity, regularity, and foresight, not even imitated by any other kind of animals or insects. All these chambers, and the passages leading to and from them, being arched, they help to support each other ; and while the interior large arches prevent them from falling into the centre, and keep the area open, the ex- terior building supports them on the outside. There are, comparatively speaking, few openings into the great area, and they, for the most part, seem intended only to admit into the nurseries that genial warmth which the dome collects. The interior building, or assemblage of nurseries, chambers, &c,, has a flattish top or roof, with- out any perforation, which M^ould keep the apartments below dry, in case through accident the dome should receive any injury, and let in water ; and it is never exactly flat and uniform, because the insects are always adding to it by building more chambers and nurseries ; so that the division or columns between the future arched apartment resemble the pinnacles on the fronts of some old buildings, and demand particular notice, as affording one proof that for the most part the insects project their arches, and do not make them by excavation. The area has also a flattish floor, which lies over the royal cham- ber, but sometimes a good height above it, having nurse- ries and magazines between. It is likewise waterproof, and contrived to let the water off" if it should get in, and run over by some short way into the subterraneous pas- sages, which run under the lowest apartments in the hill in various directions, and are of an astonishing size, being wider than the bore of a great cannon. One that Mr. Smeathman measured was perfectly cylindrical, and thirteen inches in diameter. These subterraneous pas- sages, or galleries, are lined very thick with the same kind of clay of which the hill is composed, and ascend the inside of the outward shell in a spiral manner ; and wind- ing round the whole building up to the top, intersect each other at different heights, opening either imme- diately in the dome in various places, and into the in- terior building, the new turrets, &c., or communicating WHITE ANTS. 49 with them by other galleries of different diameters, either circular or oval. From every part of these large galleries are various small covert ways, or galleries leading to different parts of the building. Under ground there are a great many that lead downward by sloping descents, three and four feet perpendicular among the gravel, whence the workers cull the liner parts, which, being kneaded up in their mouths to the consistence of mortar, become that solid clay or stone of which their hills and all their buildings, except their nurseries, are composed. Other galleries again ascend, and lead out horizontally on every side, and are carried under ground near to the surface a vast distance : for if all the nests are destroyed within a hundred yards of a house, the inhabitants of those which are left unmolested farther off, will still carry on their subterraneous galleries, and, invading it by sap and mine, do great mischief to the goods and merchandises contained in it. It seems there is a degree of necessity for the galleries under the hills being thus large, since they are the great thoroughfares for all the labourers and soldiers going forth or returning, whether fetching clay, w^ood, water, or provisions ; and they are certainly well calculated for the purposes to which they are applied by the spiral slope which is given them ; for if they were perpendicular, the labourers would not be able to carry on their build- ing with so much facility, as they ascend a perpendicular with great difficulty, and the soldiers can scarcely do it at all. It is on this account that sometimes a road like a ledge is made on the perpendicular side of any part of the building within their hill, which is flat on the upper sur- face and half an inch w ide, and ascends gradually like a staircase, or like those winding roads which are cut on the sides of hills and mountains, that would otherwise be inaccessible ; by w^hicli and similar contrivances they travel with great facility to every interior part. This, too, is probably the cause of their building a kind of bridge of one great arch, which answers the pur- pose of a flight of stairs from the floor of the area, to 50 IXSECT ARCHITECTURE. fl, A covered w.iy and nest, on the brancli of a tree, of the Termites arburum. b. Section'of the Hill-ncst of tlie Termites bellicosi, to show the interior, c, Hiil-nest of tlie Termites bellicosi, enlhe. MIIITE ANTS. 51 some opening on the side of one of the columns that sup- ])ort the great arches. This contrivance must shorten the distance exceedingly to those labourers who have the eggs to carry from the royal chamber to some of the upper nurseries, which in some hills would be four or five feet in the straightest line, and much more if carried through all the winding passages leading through the inner chambers and apartments. Mr. Smeathman found one of these bridges, half an inch broad, a quarter of an inch thick, and ten inches long, making the side of an elliptic arch of proportionable size ; so that it is wonder- ful it did not fall over or break by its own wei^^' t before they got it joined to the side of the column above. It was strengthened by a small arch at the bottom, and had a hollow or groove all the length of the upper sur- face, either made purposely for the inhabitants to travel over with more safety, or else, whicii is not improbable, worn by frequent treading. TuRRET-BuiLDIXG WhITE AsTS. , Apparently more than one species smaller than the preceding, such as the Termes niordax and 1\ atrox of Smeathman, construct nests of a very different form, the figures of which resemble a pillar, with a large mush- room for a capital. These turrets are composed of well- tempered black earth, and stand nearly three feet high. The conical mushroom-shaped roof is composed of the same material, and the brims hang over the column, being three or ibur inches wider than its perpendicular sides. Most of them, says Smeathman, resemble in shape the body of a round windmill, but some of the roofs have little elevation in the middle. When one of these turrets is completed, the insects do not afterwards enlarge or alter it ; but if it be found too small for them, they lay the foundation of another at a few inches' distance. They sometimes, but not often, begin the second before the first is finished, and a third before they have com- pleted the second. Five or six of these singular turrets in a group may be seen in the thick woods at the foot of 52 INSECT ARCHITECTURE. a tree. They are so very strongly built, that in case of violence, they will sooner tear up the gravel and solid heart of their foundation than break in the middle. When any of them happen to be thus thrown down, the insects do not abandon them : but, using their over-turned column as a basis, they run up another perpendicularly from it to the usual height, fastening the under part at the same time to the ground, to render it the more secure. Turret Nests of White Ants. One nest is represented cut tirrougli, with the upper part lying on the ground. The interior of a turret is pretty equally divided into innumerable cells, irregular in shape, but usually more or less angular, generally quadrangular or pentagonal, though the angles are not well defined. Each shell has at least two entrances ; but there are no galleries, arches, nor wooden nurseries, as in the nests of the warrior {T. bellicosus). The two species which build turret nests are very different in size, and the dimensions of the nests differ in proportion. WHITE ANTS. 63^ The White Ants or Trees Latreille's species of white ant {Tertnes hicifttgus, Rossi), formerly mentioned as found in the south of Europe, appear to have more the habits of the jet ant, described page 32, than their congeners of the tropics. They live in the interior of the trunks of trees, the wood of which they eat, and form their habitations of the galleries which they thus excavate. M. Latreille says they appear to be furnished with an acid for the purpose of softening the wood, the odour of which is exceedingly pungent. They prefer the part of the wood nearest to the bark, which they are careful not to injure, as it affords them protection. All the walls of their galleries are moistened with small globules of a gelatinous sub- stance, similar to gum Arabic. They are chiefly to be found in the trunks of oak and pine trees, and are very numerous.* Another of the species {Termes arhorwui)^ described by Smeathman, builds a nest on the exterior of trees, altogether different from any of the preceding. These are of a spherical or oval shape, occupying the arm or branch of a tree sometimes from seventy to eighty feet from the ground, and as large, in a few instances, as a sugar-cask. The composition used for a building mate- rial is apparently similar to that used by the warriors for constructing their nurseries, being the gnawings of wood in very small particles, kneaded into a paste with some species of cement or glue, procured, as iSmeathman sup- poses, partly from gummiferous trees, and partly from themselves ; but it is more probable, we think, that it is wholly secreted, like the wax of bees, by the insects themselves. With this cement, whatever may be its composition, they construct their cells, in which there is nothing very wonderful except their great numbers. They are very firmly built, and so strongly attached to the trees, that they will resist the most violent tornado. It is impossible, indeed, to detach them, except by * Latreille, Hist. Nat, Generale, torn. xiii. p. 64. 54 INSECT ARCHITECTURE. cutting them in pieces, or sawing off the branch, which is frequently done to procure the insects i'or young turkeys. (See engraving, p. 50, for a figure of this nest. ) This species very often, instead of selecting the bough of a tree, builds in the roof or wall of a house, and un- less observed in time, and expelled, occasions considerable damage. It is easier, in fact, to shut one's door against a fox or a thief, than to exclude such insidious enemies, whose aversion to light renders it difficult to trace them even when they are numerous. If we reflect on the prodigious numbers of those in- sects, and their power and rapidity of destroying, we cannot but admire the wisdom of Providence in creating so indefatigable and useful an agent in countries where the decay of vegetable substances is rapid in proportion to the heat of the climate. We have already remarked that they always prefer decaying or dead timber ; and it is indeed a very general law among insects which feed on wood to prefer what is unsound : the same prin- ciple holds with respect to fungi, lichens, and other para- sitical plants. All the species of Termites are not social ; but the solitary ones do not, like their congeners, distinguish themselves in architecture. In other respects, their habits are more similar ; for they destroy almost every substance, animal and vegetable. The most common of the solitary species must be familiar to all our readers by the name of wood-louse (Termes pulsatorium, Linn. ; Atropos lignarius, Leach) — one of the insects which produces the ticking superstitiously termed the death- tvatch. It is not so large as the common louse, but v>'hiter and more slender, having a red mouth and yellow eyes. It lives in old books, the paper on walls, collec- tions of insects and dried plants, and is extremely agile in its movements, darting, by jerks, into dark corners ibr the purpose of concealment. It docs not like to run straight forward without resting every half-second, as if to listen or look about for its pursuer, and at such resting times it is easily taken. The ticking noise is made by SPINNI>"G CATERPILLARS. 55 the insect beating against the wood with its head, and it is supjwsed by some to be peculiar to the female, and to be connected with the laying of her eggs. M. Latreille^ however, thinks that the wood-louse is only the grub of the Psocus abdominalis, in which case it could not lay eggs ; but this opinion is somewhat questionable. Ano- ther death-watch is a small beetle (Anohiwntesselatumy. 6^ INSECT ABCHITECTURE. CHAPTER XVII. Structures of Silk spun by Caterpillars, including the Silk- Worm. " Millions of spinning-worms, That in their green shops weave the smooth-hair'd silk." Milton's Comus. All the caterpillars of butterflies, moths, and, in general, of insects with four wings, are capable of spinning silk, of various degrees of fineness and strength, and differing in colour, but usually white, yellow, brown, black, or grey. This is not only of advantage in constructing nests for themselves, and particularly for their pupae, as we have so frequently exemplified in the preceding pages, but it enables them, the instant they are excluded from the Q^^^ to protect themselves from innumerable acci- dents, as well as from enemies. If a caterpillar, for in- stance, be exposed to a gust of wind, and blown off from its native tree, it lets itself gently down, and breaks its fall, by immediately spinning a cable of silk, along which, also, it can reascend to its former station when the danger IS over. In the same way, it frequently disappoints a bird that has marked it out for prey, by dropping hur- riedly down from a branch, suspended to its never-fiailing delicate cord. The leaf-rollers, formerly described, have the advantage of other caterpillars in such cases, by being able to move as quickly backwards as forwards ; so that when a bird puts in its bill at one end of the roll, the insect makes a ready exit at the other, and drops SPINNIXG CATERPILLARS. 57 along its thread as low as it judges convenient. We have seen caterpillars drop in this way from one to six feet or more ; and by means of their cable, which they are careful not to break, they climb back with great expedi- tion to their former place. The structure of their legs is well adapted for climbing up their singular rope — the six fore-legs being furnished with a curved claw ; while the pro-legs (as they have been termed) are no less fitted for holding them firm to the branch when they have regained it, being con- structed on the principle of forming a vacuum, like the leather sucker with which boys lift and drag stones. The foot of the common fly has a similar sucker, by which it is enabled to walk on glass, and otherwise support itself against gravity. The different forms of the leg and pro- leg of a spinning caterpillar are represented in the figure. Leg and Pro-leg of a Caterpillar, greatly magnified. In order to understand the nature of the apparatus by which a caterpillar spins its silk, it is to be recollected that its whole interior structure differs from that of warm- blooded animals. It has, properly speaking, no heart, though a long tubular dorsal vessel, which runs along the back, and pulsates from twenty to one hundred times per minute, has been called so by Malpighi and others : but neither Lyonnet nor Cuvier could detect any vessel issuing from it; and consequently the fluid which is analogous to blood has no circulation. It differs also VOL. II. D 68 INSECT ARCHITECTURE. from the higher orders of animals in having no brain, the nerves running along the body being only united by little knobs, called ganglions. Another circumstance is, that it has no lungs, and docs not breathe by the mouth, but by air-holes, or spiracles, eighteen in number, situ- ated along the sides, in the middle of the rings, as may be seen in the following figure from Lyonnet. Caterpillar of the Goat-Moth (^Cossus ligniperda). These spiracles communicate on each side with tubes, that have been called the wind-pipes (trachea). The spinning apparatus is placed near the mouth, and is con- nected with the silk-bags, which are long, slender, float- ing vessels, containing a liquid gum. The bags are closed at their lower extremity, become wider towards the middle, and more slender towards the head, where they unite to form the spinning-tube, or spinneret. The bags being in most cases longer than the body of the caterpillar, necessarily lie in a convoluted state, like the intestines of quadrupeds. The capacity, or rather the length, of the silk-bags, is in proportion to the quantity of silk required ibr spinning ; the Cossits ligniperda, for example, from living in the wood of trees spins little, having a bag only one-fourth the length of that of the silk-worm, though the caterpillar is at least twice the dimensions of the latter. The following figure, taken from the admirable treatise of Lyonnet on the anatomj^ of the Cossus, will render these several organs more easily understood than any description. The spinneret itself was supposed by Reaumur to have two outlets for the silk ; but Lyonnet, upon minute dissection, found that the two tubes united into one be- fore their termination ; and he also almost assured him- self that it was composed of alternate slips of horny and SPINNING CATKRPILLARS. 59 D 2 CfO 1>SECT ARCIIITECTUKE. membranaceous substance, — the one for pressing the thread into a small diameter, and the other for enlarging it at the insect's pleasure. It is cut at the end somewhat like a writing-pen, though with less of a slope, and is admirably fitted for being applied to objects to which it may be required to attach silk. The following are magnified figures of the spinneret of the Cossus, from Lyonnet. Side-view of the Silk-tube. Section of the Silk-tube, magnified 22,000 times. " You may sometimes have seen," says the Abbe de la Pluche, "in the work-rooms of goldsmiths or gold- wire- drawers, certain iron plates, pierced with holes of different calibres, through which they draw gold and silver wire, in order to render it finer. The silk-worm has under her mouth such a kind of instrument, perfo- rated with a pair of holes [united into one on the out- side*], through which she draws two drops of the gum that fills her two bags. These instruments are like a pair of distaffs for spinning the gum into a silken thread. She fixes the first drop of gum that issues where she pleases, and then draws back her head, or lets herself fall, while the gum, continuing to flow, is drawn out and lengthened into a double stream. Upon being exposed to the air, it immediately loses its fluidity, becomes dry, and acquires consistence and strength. She is never de- ceived in adjusting the dimensions of the [united] aper- tures, or in calculating the proper thickness of the * Lyonnet. SPINNING CATERPILLAKS. 61 Labiuin, or lower lip of Cossas. — a. Silk-tube. thread, but invariably makes the strength of it propor- tionable to the weight of her body. " It would be a very curious thing to know how the gum which composes the silk is separated and drawn off from the other juices that nourish the animal. It must be accomplished like the secretions formed by glands in the human body. I am therefore persuaded that the gum- bags of the silk- worm are furnished with a set of minute glands, which, being impregnated with gum, alFord a free passage to all the juices of the mulberry- leaf corresponding with this glutinous matter, while they exclude every fluid of a ditterent quahty."* When con- fined in an open glass vessel, the goat-moth caterpillar will effect its escape by constructing a curious silken ladder, as represented by Roesel. Caterpillars, as they increase in size, cast their skins as lobsters do their shells, and emerge into renewed ac- tivity under an enlarged covering. Previous to this change, when the skin begins to gird and pinch them, they may be observed to become languid, and indifferent to their food, and at length they cease to eat, and await * S^.ectacle de la Xatuie, vol. i. 62 INSECT ARCHITECTUBE. the slou^hingf of their skin. It is now that the faculty of spinning silk seems to be of great advantage to them ; for being rendered inactive and helpless by the tighten- ing of the old skin around their expanding body, they might be swept away by the first puff of wind, and made prey of by ground beetles or other carnivorous prowlers. To guard against such accidents, as soon as they feel that they can swallow no more food, from being half choked by the old skin, they take care to secure themselves from danger by moorings of silk spun upon the leaf or the branch where they may be reposing. The caterpillar of the white satin-moth (^Leuco}na salicis, Stephens) in this way draws together with silk one or two leaves, similar to the leaf-rollers (^Torfricidce), though it always feeds openly without any covering. The caterpillar of the puss-moth again, which, in its third skin, is large and heavy, spins a thick web on the upper surface of a leaf, to which it adheres till the change is effected. The most important operation, however, of silk-spin- ning is performed before the caterpillar is transformed into a chrysalis, and is most remarkable in the caterpillars of moths and other four-winged flies, with the exception of those of butterflies ; for though these exhibit, perhaps, greater ingenuity, they seldom spin more than a few threads to secure the chrysalis from falling, whereas the others spin for it a complete envelope or shroud. Wc have already seen, in the preceding pages, several striking instances of this operation, when, probably for the purpose of husbanding a scanty supply of silk, ex- traneous substances are worked into the texture. In the case of other caterpillars, silk is the only material em- ployed. Of this the cocoon of the silk-worm is the most prominent example, in consequence of its import- ance in our manufactures and commerce, and on that account will demand from us somewhat minute details, though it would require volumes to incorporate all the information which has been published on the subject. SLLIw-WOBM. G3 Sllk-Wokm. The silk-worm, like most other caterpillars, changes its skin four times during its growth. The intervals at which the four moultings follow each other depend much on climate or temperature, as well as on the quality and quantity of food. It is thence found, that if they are exposed to a high temperature, say from 81° to 100^ Fahrenheit, the moultings will be hastened ; and only five days will be consumed in moulting the third or fourth time, whilst those worms that have not been hastened take seven or eight days.* The period of the moultings is also influenced by the temperature in w^hich the eggs have been kept during the winter. When the heat of the apartment has been regulated, the first moulting takes place on the fourth or fifth day after hatching, the second begins on the eighth day, the third takes up the thirteenth and fourteenth days, and the last occurs on the twenty-second and twenty-third days. The fifth age, in such cases, lasts ten days, at the end of which, or thirty -two da^^s after hatching, the caterpillars attain their full growth, and ought to be three inches in length ; but if they have not been properly fed, they will not be so long. With the age of the caterpillar, its appetite increases, and is at its maximum after the fourth moulting, when it also attains its greatest size. The silk gum is then elaborated in the reservoirs, while the caterpillar ceases to eat, and soon diminishes again in size and weight. This usually requires a period of nine or ten days, com- mencing from the fourth moulting, after which it begins to spin its shroud of silk. In this operation it proceeds with the greatest caution, looking carefully for a spot in which it may be most secure from interruption. " We usually," says the Abbe de la Pluche, " give it some little stalks of broom, heath, or a piece of paper rolled up, into which it retires, and begins to move its head to different places, in order to fasten its thread on * Cours d' Agriculture, par M. Rozier. Paris, 1801. 64 INSECT ARCHITECTURE. every side. All this work, though it looks to a bystander like confusion, is not without design. The caterpillar neither arranges its threads nor disposes one over another, but contents itself with distending a sort ol^ cotton or floss to keep off the rain ; for Nature having ordained silk-worms to work under trees, they never change their method, even when they ai'e reared in our houses. " When my curiosity led me to know how they spun and placed their beautiful silk, I took one of them, and frequently removed the floss with which it first attempted to make itself a covering ; and as b}^ this means I weakened it exceedingly, when it at last became tired ot beginning anew, it fastened its threads on the first thing it encountered, and began to spin very regularly in ray presence, bending its head up and down, and crossing to every side. It soon confined its movements to a very contracted space, and, by degrees, entirely surrounded itself with silk ; and the remainder of its operations became invisible, though these may be miderstood from examining the work after it is finished. In order to complete the structure, it must draw out of the gum-bag a more delicate silk, and then with a stronger gum bind all the inner threads over one another. " Here, then, are three coverings entirely different, which afford a succession of shelter. The outer loose silk, or floss, is for keeping oft" the rain ; the fine silk in the middle prevents the wind from causing injury ; and the glued silk, which composes the tapestry of the chamber where the insect lodges, repels both air and water, and prevents the intrusion of cold. " After building her cocoon, she divests herself of her fourth skin, and is transformed into a chrysalis, and subsequently into a moth (Bomb i/jc mor'i), when, without saw or centre-bit, she makes her way through the shell, the silk, and the floss ; for the Being who teaches her how to build herself a place of rest, where the delicate limbs of the moth may be formed without interruption, instructs her likewise how to open a passage for escape. " The cocoon is like a pigeon's e^^, and more pointed SILK- WORM. 65 at one end than the other ; and it is remarkable that the caterpillar does not interweave its silk towards the pointed end, nor apply its glue there as it does in every other part,* by bending itself all around with great pliantness and agility : what is more, she never tails, when her labour is finished, to fix her head opposite to the pointed extremity. The reason of her taking this position is, that she has purposely left this part less strongly cemented, and less exactly closed. She is instinctively conscious that this is to be the passage for the perfect insect which she carries in her bowels, and has therefore the additional precaution never to place this pointed extremity against any substance that might obstruct the moth at the period of its egress. " When the caterpillar has exhausted herself to furnish the labour and materials of the three coverings, she loses the form of a worm, her spoils drop all around the chrysalis ; first throwing off her skin, with the head and jaws attached to it, and the new skin hardening into a sort of leathery consistence. Its nourishment is already in its stomach, and consists of a yellowish mucus, but gradually the rudiments of the moth unfold themselves, — the wings, the antennae, and the legs becoming solid. In about a fortnight or three weeks, a slight swelling in the chrysalis may be remarked, which at length produces a rupture in the membrane that covers it, and by repeated effoi'ts the moth bursts through the leathery envelope into the chamber of the cocoon. *' The moth then extends her antennae, together with her head and feet, towards the point of the cone, which not being thickly closed up in that part gradually yields to her efforts ; she enlarges the opening, and at last comes forth, leaving at the bottom of the cone the ruins of its former state — namely, the head and entire skin of the caterpillar, which bear some resemblance to a heap of foul linen. "f Reaumur was of opinion that the moth makes use of * This is denied by recent observers, ■j" Spectacle de la Nature, vol. i. d3 66 INSECT ARCHITECTURE. its eyes as a file, in order to effect its passage through the silk ; while Malpighi, Peck, and others, believe that it is assisted by an acid which it discharges in order to dissolve the gum that holds the fibres of the silk together (seep. 184). Mr. Swayne denies that the threads are broken at all, either by filing or solution ; for he suc- ceeded in unwinding a whole cocoon from which the moth had escaped. The soiling of the cocoon by a fluid, however, we may remark, is no proof of the acid ; for all moths and butterflies discharge a fluid when they assume wings, whether they be inclosed in a cocoon or not ; but it gives no little plausibility to the opinion, that " the end of the cocoon is observed to be wetted for an hour, and sometimes several hours, before the moth makes its way out."* Other insects employ different contrivances for escape, as we have already seen, and shall still further exemplify. It is the middle portion of the cocoon, after removing the floss or loose silk on the exterior, which is used in our manufactures ; and the first preparation is to throw the cocoons into warm water, and to stir them about with twigs, to dissolve any slight gummy adhesions which may have occurred when the caterpillar was spinning. The threads of seYcral cones, according to the strength of the silk wanted, are then taken and wound off' upon a reel. The refuse, consisting of what we may call the tops and bottoms of the cones, are not wound, but carded, like wool or cotton, in order to form coarser fabrics. We learn from the fact of the cocoons being generally unwound without breaking the thread, that the insect spins the whole without interruption. It is popularly supposed, however, that if it be disturbed during the operation by any sort of noise, it will take alarm, and break its thread ; but Latreille says this is a vulgar error.'!' * Count Dandolo's Art of Rearing Silk-Worms, Eng. Transl., p. 215. f On a tort de croire que le bruit nuise a ces insectes* Hist. Nat. Geueiale, vol. xiii. p. 170. SlLK->YOIiM. 67 The length of the unbroken thread in a cocoon varies from six hundred to a thousand feet ; and as it is all spun double by the insect, it will amount to nearly two thousand feet of silk, the whole of which does not weigh above three grains and a half: five pounds of silk from ten thousand cocoons is considerably above the usual average. When we consider, therefore, the enormous quantity of silk which is used at present, the number of worms employed in producing it will almost exceed our comprehension. The manufacture of the silk, indeed, gives employment, and furnishes subsistence, to several millions of human beings ; and we may venture to say, that there is scarcely an individual in the civilized world who has not some article made of silk in his pos- session. In ancient times, the manufacture of silk was confined to the East Indies and China, where the insects that produce it are indigenous. It was thence brought to Europe in small quantities, and in early times sold at so extravagant a price, that it was deemed too expensive even for royalty. The Emperor Aurelian assigned the expense as a reason for refusing his empress a robe of silk ; and our own James I., before his accession to the crown of England, had to borrow of the Earl of Mar a pair of silk stockings to appear in before the English ambassador, a circumstance which probably led him to promote the cultivation of silk in England.* The Roman authors were altogether ignorant of its origin, — • some supposing it to be grown on trees as hair grows on animals, — others that it Mas produced by a shell-fish similar to the mussel, which is known to throw out threads for the purpose of attaching itself to rocks, — • others that it was the entrails of a sort of spider, which was fed for four years with paste, and then with the leaves of the green willow, till it burst with fat, — and others that it was the produce of a worm which built nests of clay and collected wax. The insect was at length spread into Persia ; and eggs were afterwards, at Shaw's Gen. Zoology, vol. vi. 68 INSECT ARCHITECTURE. the instance of the Emperor Justinian, concealed m hollow canes by two monks, and conveyed to the isle of Cos. This emperor, in the sixth century, caused them to be introduced into Constantinople, and made an object of public utility. They were thence successively culti- vated in Greece, in Arabia, in Spain, in Italy, in France, and in all places where any hope could be indulged of their succeeding. In America the culture of the silk- worm was introduced into Virginia in the time of James I., who himself composed a book of instructions on the subject, and caused mulberry-trees and silk- worms' eggs to be sent to the colony. In Georgia, also, lands were granted on condition of planting one hundred white mulberry-trees on every ten acres of cleared land.* The growth of the silk- worm has also been tried, but with no great success, in this country. Evelyn computed that one mulberry-tree would feed as many silk-worms annually as would produce seven pounds of silk. " Ac- cording to that estimate," says Barham,f " the two thou- sand trees already planted in Chelsea Park (which take up one-third of it) will make 14,000 lbs. weight of silk ; to be commonly worth but twenty shillings a pound, those trees must make 14,000/. per annum." During the last cen- tury, some French refugees in the south of Ireland made considerable plantations of the mulberry, and had begun the cultivation of silk with every appearance of success ; but since their removal the trees have been cut down, j In the vicinity of London, also, a considerable plantation of mulberry-trees was purchased by the British, Irish, and Colonial Silk Company in 1825; but we have not learned whether this Company have any active measures now in operation. The manufacture of silk was introduced into this coun- try in 1718, at Derby, by Mr. John Lombe, who tra- velled into Italy to obtain the requisite information ; but so jealous were the Italians of this, that according * North American Review, Oct. 1828, p. 449. f Essay on the Silk-Worm, p. 95. London, 1719. 1 Preface to Dandolo on the Silk-Worm, Eng. Trans!., p. xiii. EMPEROR-MOTH. 69 to some statements which Jbave obtained belief, he fell a victim to their revenge, having been poisoned at the early age of twenty-nine.* There are not only several varieties of the common silk-worm {Bombijx mori), but other species of cater- pillars, which spin silk capable of being manufactured, though not of so good qualities as ^le common silk. None of our European insects, however, sieem to be well fitted for the purpose, though it has been proposed by Fabricius and others to try the crimson under-wing (Ca- tocala sponsa, Schraxk), &c. M. Latreille quotes from the ' Recreations of Natural History,' by Wilhelm, the statement that the cocoons of the emperor-moth {Saiur- 7iia pavofiia) had i^en successfully tried in Germany, by M. Wentzel IIeg^fei^:^de Berchtoldsdorf, under an imperial patent. ^ Emperor-Moth. The emperor-moth, indeed, is no less worthy of our attention with respect to the ingenuity of its architecture than the beauty of its colours, and has consequently at- tracted the attention of every Entomologist. The cater- pillar feeds on fruit-trees and on the willow, and spins a cocoon, in form of a Florence flask, of strong silk, so thickly Avoven that it appears almost like damask or leather. It differs from most other cocoons in not being closed at the upper or smaller end, which terminates in a narrow circular aperture, formed by the convergence of little bundles of silk, gummed together, and almost as elastic as whalebone. In consequence of all these ter- minating in needle-shaped points, the entrance of depre- dators is guarded against, upon the principle which pre- vents the escape of a mouse from a wire trap. The insect, however, not contented with this protection, con- structs another in form of a canopy or dome, within the external aperture, so as effectually to shield the chrysalis from danger. We have formerly remarked (page 181) * Glover's Directory of the County of Derby, Introd., p. xvi. 70 INSECT ARCIIITECTUKE. that the caterpillar of the jEgei'ia asUifonnis of Ste- phens in a similar way did not appear to be contented with a covering- of thin wood, without an additional bon- net of brown wax. The cocoon of the emperor-moth, Cocoons of the Emperor-moth, cut open to show their structure. though thus in some measure impenetrable from without, is readily opened from within ; and when the moth issues from its pupa case, it easily makes its way out without either the acid or eye-files ascribed to the silk-worm. The elastic silk gives way upon being pushed from within, and when the insect is fairly out, it shuts again of its own accord, like a door with spring hinges, — a circumstance which at first puzzled Roesel not a little when he saw a fine large moth in his box, and the cocoon apparently in the same state as when he had put it there. Another naturalist conjectures that the converging threads are intended to compress the body of the moth as it emerges, in order to force the fluids into the nervures of the wings ; for when he took the chrysalis previously out of the cocoon, the wings of the moth never expanded properly.* Had he been much conversant with breeding insects, he M'ould rather, * Meinecken, quoted by Kirby and Spence, iii. 280. MOTHS. 71 we think, have imputed this to some injury which the chrysalis had received. We have witnessed the shrivel- ing of the wings which he alludes to, in many instances, and not unfrequently in butterflies which spin no cocoon. The shriveling, indeed, frequently arises from the want of a sufficient supply of food to the caterpillar in its last stage, occasioning a deficiency in the fluids. The elasticity of the cocoon is not peculiar to the em- peror-moth. A much smaller insect, the green cream- border-moth {Tortrix clilorcuui) before mentioned (page 163), for its ingenuity in bundling up the expanding leaves of the willow, also spins an elastic shroud for its chrysalis, of the singular shape of a boat with the keel uppermost. Like the caterpillar of Pyralis strigulalls (page 187), whose building, though of different mate- rials, is exactly of the same form, — it first spins two ap- proximating walls of whitish silk, of the form required, and when these are completed, it draws them forcibly together with elastic threads, so placed as to retain them closely shut. The passage of the moth out of this cocoon might have struck Roesel as still more marvel- lous than that of his emperor, in which there was at least a small opening ; while in the boat cocoon there is none. We have now before us two of these, which we watched the caterpillars through the process of build- ing, in the summer of 1828, and from one only a moth issued, — the other, as often happens, having died in the chrysalis. But what is most remarkable, it is impossible by the naked eye to tell which of these two has been opened* by the moth, so neatly has the joining been finished. (J. R.) Some species of moths spin a very slight silken tissue for their cocoons, being apparently intended more to retain them from falling than to afibrd protection from other accidents. The gipsy-moth {Hypogymna cUspar), rare in most parts of Britain, is one of these. It selects for its retreat a crack in the bark of the tree upon which it feeds, and over this spins only a few straggling threads. We found last summer (1829), in the hole of an elm- tree in the Park at Brussels, a group of half a dozen of 72 INSECT ARCHITECTURE. these, that did not seem to have spun any covering at all, but trusted to a curtain of moss (^Hi/pjia) which mar- gined the entrance. (J. R.) In a species nearly allied to this, the yellow-tussock (Dasi/chira pudibimtla, Ste- phens), the cocoon, one of which we have now before us, is of a pretty close texture, and interwoven with the long hairs of the caterpillar itself (see figure b, page 22), which it plucks out piece-meal during the process of building, — as is also done by the vapourer (^Oryyia an- tiqua, Hubner), and many others. These are additional instances of the remarks we for- merly made, that caterpillars which spin a slight web are transformed into perfect insects in a much shorter period than those which spin more substantial ones. Thus the cream-spot tiger {Arctia v'dUca, Stephexs) lies in chrysalis only three weeks, and therefore does not re- quire a strong web. It is figured below, along with another, which is still slighter, though more ingeniously woven, being regularly meshed like net-work. A very prettily-netted cocoon is constructed by the Cocoon of Arctia villica.' Net-work cocoon . SPI^'N1NG CATERPIIXARS. 73 grub of a very small grey weevil (^Hijpera Rumicis)^ which is not uncommon in July, on the seed spikes of docks (B amices). This cocoon is globular, and not larger than a garden pea, though it appears to be very large in proportion to the pupa of the insect, reminding us not a little of the carved ivory balls from China. The meshes of the net-work ai'e also large, but the materials are strong and of a wa^y consistence. Upon remarking that no netting was ever spun over the part of the plant to which the cocoon was attached, we endeavoured to make them spin cocoons perfectly globular, by detaching them when nearly finished ; but though we tried fom* or five in this way, we could not make them add a single mesh after removal, all of them making their escape through the opening, and refusing to re-enter in order to complete their structure. (J. R.) The silk, if it may be so termed, spun by many species of larvag is of a still stronger texture than the waxy silk of the little weevil just mentioned. We recently met with a remarkable instance of this at Lee, in the cocoons of one of the larger ichneumons i^Ophion VinalcB? Stephens), inclosed in that of a puss-moth {Cerura Vinida) — itself remarkable for being composed of sand as well as wood, the fibres of which had been scooped out of the under-ground cross-bar of an old paling, to which it was attached. But the most singular portion of this was the junction of the outer wall with the edges of the hollow thus scooped out, Mhich was formed of fibres of wood placed across the fibres of the bar nearly at right angles, and strongly cemented together, as if to form a secure foundation for the building. In this nest were formed, surreptitiously introduced into the original building, five empty cells of a black colour, about an inch long, and a sixth of an inch in diameter ; nearly cylindrical in form, but somewhat flattened ; vertical and parallel to one another, though slightly cm*ved on the inner side. The cells are com- posed of strong and somewhat coarse fibres, more like the carbonized rootlets of a tree than silk, and resembling in texture a piece of coarse milled cloth or felt, such as is 74 IXSECT ARCHITECTURE. Kest of Puss-moth, inclosing five cocoons of an Ichnsumon. Natural size. used for the bases of plated hats. It is worthy of re- mark, that all these cells opened towards one end, as if the caterpillars which constructed them had been aware that the wall of the puss-moth, in which the flies would have to make a breach, was very hard, and would require their united efforts to eftect an escape. The importance of such a precaution will appear more strikingly, when we compare it with the instance formerly mentioned (page 185), in which only one ichneumon had been able to force its way out. (J. R.) It appears indispensable to some grubs to be confined within a certain space in order to construct their cocoons. We saw this well exemplified in the instance of a grub of one of the mason-bees (^Osmia bicor?iis), which we took from its nest, and put into a box, with the pollen paste which the mother bee had provided for its subsist- ence. (See pages 43, 44.) When it had completed its growth, it began to spin, but in a very awkward manner — attaching threads, as if at random, to the bits of pollen which remained undevoured, and afterwards tumbling about to another part of the box, as if dissatisfied with what it had done. It sometimes persevered to spin in one place till it had formed a little vaulted wall ; but it SP12»X1JSG CATJiRriLLABS. 75 abandoned at the least three or four of these in order to begin others, till at length, as if compelled by the ex- treme urgencj of the stimulus of its approaching change, it completed a shell of shining brown silk, woven into a close texture. Had the grub remained within the narrow- clay cell built for it by the mother bee, it would, in all probability, not have thus exhausted itself in vain efforts at building, which were likely to prevent it from ever arriving at the perfect state — a circumstance which often happens in the artificial breeding of insects. This bee, however, made its appearance the following sprins:. (J. R.) Beside silk, the cocoons of many insects are composed of other animal secretions, intended to strengthen or otherwise perfect their texture. We have already seen that some caterpillars pluck off their own hair to inter- weave amongst their silk ; there are others which pro- duce a peculiar substance for the same purpose. The lackey caterpillar (^Clisiocampa neustria, Curtis) in this manner lines its cocoon with pellets of a downy sub- stance, resembling little tufts of the flowers of sulphur. The small egger, again (^Eriog aster lanestris, Germak), can scarcely be said to employ silk at all, — the cocoon being of a uniform texture, looking, at first sight, like dingy Paris plaster, or the shell of a pheasant's eg:g ; but upon being broken, and inspected narrowly, a few threads of silk may be seen interspersed through the whole. In size it is not larger than the egg of the gold-crested wren. It has been considered by Brahm a puzzling cir- cumstance, that this cocoon is usually perforated with one or two little holes, as if made by a pin from with- out ; and Kirby and S pence tell us that their use has not been ascertained.* May they not be left as air-holes for the included chrysalis, as the close texture of the cocoon might, without this provision, prove fatal to the animal ? Yet, on comparing one of these with a similar cocoon of the large egger-moth (^Lasiocanipa Quercus), we find no air-holes in the latter, as we might have been led to * Brahm's Ins. Nat. 289, and Kirby and Speiice's lutr. iii. 223. 76 INSECT ARCHITECTURE. expect from the closeness of its texture. We found a cocoon of a saw-fly {^Trichioboma), about the same size as that of the egger, attached to a hawthorn twig, in a hedge at New-Cross, Deptlord, but of a leatliery texture, and, externally, exactly the colour of the bark of the tree. During the summer of 1830 we found a consider- able number of the same cocoons. These were all with- out air-holes. The egger, we may remark, unlike the dock-weevil or the bee-grub just mentioned, can work her cocoon without any point of attachment. We had a colony of these caterpillars in the summer of 1825, brought from Epping Forest, and saw several of them ■work their cocoons, and we could not but admire the dexterity with which they avoided filling up the little pin-holes. The supply of their building material was evidently measured out to them in the exact quantity re- quired ; for when we broke down a portion of their wall, by way of experiment, they did not make it above half the thickness of the previous portion, though they plainly preferred having a thin wall to leaving the breach mi- closed. (J. R.) Several species of caterpillars, that spin only silk, are social, like some of those we formerly mentioned, which unite to form a common tent of leaves (^see pages 165, 166). The most common instance of this is in the caterpillars which feed on the nettle — the small tortoise-shell (^Vanessa uriicce), and the peacock's eye^(F. /). Colonies of these may be seen, after Midsummer, on almost every clump of nettles, inhabiting a thin web of an irregular oval shape, from which they issue out to feed on the leaves, always returning when their appetite is satisfied, to assist their companions in extending their premises. Other examples, still more conspicuous from being seen on fruit-trees and in hedges, occur in the caterpillars of the small ermine-moth (^Yponomeiita padella), and of the lackey (^Clisiocampa Jieustria), which in some years are but too abundant, though in others they are seldom met with. In the summer of 1826, every hedge and fruit-tree around London swarmed with colonies of the ermine, though it has not since been SPINNING CATERPILLARS. 77 plentiful ; and in the same way, during the summer of 1829, the lackeys were to be seen every where. We mention this irregularity of appearance that our readers may not disappoint themselves by looking for what is not always to be found. It is probable, that in 1830, the lackeys will be few, for, notwithstanding the myriads of caterpillars last summer, we saw only a single moth of this species, and out of a number of chrysalides which a young friend had in his nurse-boxes, not one moth was bred. The caterpillars of other moths, which are in some years very common— such as the brown-tail (Porthesia aurijiua), and the golden-tail (P. Chri/sorrhcpa), are also social ; and, as the eggs are hatched late in the summer, the brood passes the winter in a very closely woven nest of warm silk. This is usually represented as composed of leaves which have had their pulpy parts Winter nest of the Social Caterpillars of the Brown-tail Motb {Pcrrthesia aurifitia^ figured rom specimen. 78 INSECT ARCHITECTURE. eaten as food by the colonists ; but from minute observa- tion of at least twenty of these nests in the winter of 1828-9, we are quite satisfied that leaves are only an accidental, and not a necessary, part of the stiucture. When a leaf happens to be in the line of the walls of the nest, it is included ; but there is no apparent design in pressing it into the service, nor is a branch selected because it is leafy. On the contrary, by far the greater number of these nests do not contain a single leaf, but are composed entirely of grey silk. In external form, no two of these nests are alike ; as it depends entirely upon the form of the branch. When, therefore, there is only one twig, it is somewhat egg-shaped ; but when there are several twigs, it commonly joins each, assuming an angular shape, as maybe seen in the preceding figure. This irregularity arises from the circumstance of each individual acting on its own account, without the direc- Winter nests o( Poithesia chrysorrhaa, one bciri";; cut open to show the chambers. T lie dots represent the cgesta of the caterpillars. SPIKNIXG CATERPILLARS. 79 tion or superintendence of the others. The interior of the structure is, for the same reason, more regular, being divided into compartments, each of which forms a cham- ber for one or more individuals. Previous to the cold weather, these chambers have but slight partitions ; but before the frosts set in the whole is made thick and warm. A no less remarkable winter nest, of a small species of social caterpillar, is described by M. Bonnet, which we omitted to introduce when treating of the Glanville fritillary (page 164). The nest in question is literally pendulous, being hung from the branch of a fruit-tree by a strong silken thread. It consists of one or two leaves neatly folded, and held together with silk, in which the caterpillars live harmoniously together. Pendulous leaf iiests, from Bonnet. In a recently published volume of ' Travels in Mexico,' we find a very remarkable account of some pendulous nests of caterpillars, which appear to be almost as curi- ous as the nests of the pasteboard-making wasps, de- scribed at p. 87. The author of these Travels does not define the species of caterpillar whose constructions at- tracted his observation. He says, *' After having as- cended for about an hour, we came to the region of oaks and other majestically tall trees, the names of which I «J0 insect AKCIIITECTUEE. could not learn. Suspended from their stately branches, were innumerable nests, enclosed, apparently, in white paper bags, in the manner of bunches of grapes in Eng- land, to preserve them from birds and flies. I had the curiosity to examine one of them, which I found to con- tain numberless caterpillars. The texture is so strong that it is not easily torn ; and the interior contained a quantity of green leaves, to support the numerous pro- geny M'ithin." * In all the nests of social caterpillars, care is taken to leave apertures for passing out and in. It is remarkable, also, that however far they may ramble from their nest, they never fail to find their way back when a shower oi rain or nightfall renders shelter necessary. It requires no great shrewdness to discover how they effect this ; for by looking closely at their track it will be found that it is carpeted with silk — no individual moving an inch without constructing such a pathway, both for the use of his companions and to facilitate his own return. All these social caterpillars, therefore, move more or less in processional order, each following the road which the first chance traveller has marked out with his strip of silk carpeting. There are some species, however, which are more remarkable than others in the regularity of their proces- sional marchings, particularly two which are found in the south of Europe, but are not indigenous in Britain. The one named by Reaumur the processionary {Cnetlio- campa processio?iea, Stephens) feeds upon the oak ; a brood dividing, when newly hatched, into one or more parties of several hundred individuals, which afterwards unite in constructing a common nest nearly two feet long, and from four to six inches in diameter. As it is not divided like that of the brown-tails into chambers, but consists of one large hall, it is not necessary that there should be more openings than one ; and accord- ingly, when an individual goes out and carpets a path, the whole colony instinctively follow in the same track, * Hardy's Travels in the Interior of Mexico, p. 32. SPINNING CATERPILLARS. 11 though from the immense population they are often compelled to march in parallel files from two to six deep. The procession is always headed by a single caterpillar ; sometimes the leader is immediately followed by one or two in single file, and sometimes by two abreast, as re- presented in the cut. A similar procedure is followed by a species of social caterpillars which feed on the pine in Savoy and Languedoc ; and though their nests arc not half the size of the preceding, they are more worthy of notice, from the strong and excellent quality of their silk, which Reaumur was of opinion might be advan- tageously manufactured. Their nests consist of more chambers than one, but are furnished with a main en- trance, through which the colonists conduct their forag- ing processions. Is'est and order of mavchin? of the Proc>3Ssionan,- Caierpillirs of the oak '^Cntthocampa processioneli). VOL. ir. 82 INSECT ARCHITECTURE. CHAPTER XVIII. Structures of Spiders. Modern naturalists do not rank spiders among insects, because they have no antennas, and no division between the head and the shoulders. They breathe by leaf-shaped gills, situated under the belly, instead of spiracles in the sides ; have a heart connected with these ; have eight legs instead of six ; and eight fixed eyes. But as spiders are popularly considered insects, it will sufficiently suit our purpose to introduce them here as such. The apparatus by which spiders construct their inge- nious fabrics is much more complicated than that which we have described as common to the various s])ecies of caterpillars. Caterpillars have only two reservoirs for the materials of their silk ; but spiders, according to the dissections of M. Treviranus, have four principal vessels, two larger and two smaller, with a number of minute ones at their base. Several small tubes branch towards the reservoirs, for carrjnng to them, no doubt, a supply of the secreted material. Swammerdam describes them as twisted into many coils of an agate colour.* We do not find them coiled, but nearly straight, and of a deep yellow colour. From these, when broken, threads can be drawn out like those spun by the spider, though we cannot draw them so fine by many degrees. From these little flasks or bags of gum, situated near the apex of the abdomen, and not at the mouth; as in caterpillars, a tube originates, and terminates in the ex- ternal spinnerets, which may be seen by the naked eye in the larger spiders, in the form of five little teats sur- rounded by a circle, as represented in the following figure. * Hill's Swammerdam, part i. p. 23. SPIDERS. 83 Garden Spider {Epeira dlademd), suspended by a thread proceeding from its spinneret. We have seen that the silken thread of a caterpillar is composed of two united within the tube of the spinneret, but the spider's thread would appear, from the first view of its five spinnerets, to be quintuple, and in some spe- cies which have six teats, so many times more. It is not safe, however, in our interpretations of nature to proceed upon conjecture, however plausible, nor to take anything for granted which we have not actually seen ; since our inferences in such cases are almost certain to be erroneous. If Aristotle, for example, had ever looked narrowly at a spider when spinning, he could not have fancied, as he does, that the materials which it uses are nothing but wool stripped from its body. On looking, then, with a strong magnifying glass, at the teat-shaped E 2 84 INSECT ARCHITECTURE. spinnerets of a spider, we perceive them studded with regular rows of minute bristle-like points, about a thou- sand to each teat, making in all from five to six thousand. These are minute tubes which we may appropriately term sp'umerides, as each is connected with the internal reservoirs, and emits a thread of inconceivable fineness. In the figure below, this wonderful apparatus is repre- sented as it appears in the microscope. Spinnerets of a Spider magnified to show tlie Spinnerules. We do not recollect that naturalists have ventured to assign any cause for this very remarkable multiplicity of the spinnerules of spiders, so difi'erent from the simple spinneret of caterpillars. To us it appears to be an ad- mirable provision for their mode of life. Caterpillars neither require such strong materials, nor that their thread should dry as quickly. It is well known in our manufactures, particularly in rope-spinning, that in cords of equal thickness, those which are composed of many smaller ones united are greatly stronger than those which are spun at once. In the instance of the spider's thread, this principle must hold still more strikingly, inasmuch as it is composed of fluid materials that require to be dried rapidly, and this drying must be greatly facilitated SPIDERS. 85 by exposing so many to the air separately before their ufiion, which is effected at the distance of about a tenth of an incli from the spinnerets. In the following figure each of the threads represented is reckoned to contain one hundred minute threads, the whole forming only one of the spider's common threads. A single tlivead of a Spider, £;reatly ma^jiiified, so that, for the small space repvesfuted, the liues are sliowu as parallel. Leeuwenhoeck, in one of his extraordinary microsco- pical observations on a young spider not bigger than a grain of sand, upon enumerating the threadlets in one of its threads, calculated that it would require four millions of them to be as thick as a hair of his beard. Another important advantage derived by the spider from the multiplicity of its threadlets is, that the thread affords a much more secure attachment to a wall, a branch of a tree, or any other object, than if it were simple ; for, upon pressing the spinneret against the object, as spiders always do when they fix a thread, the spinnerules are extended over an area of some diameter, from every 86 INSECT ARCHITECTURE. hair's breadth of which a strand, as rope-makers term it, is extended to compound the main cord. The following figme exhibits this ingenious contrivance. Attached end of a Spirt's thread magnified. Those who maybe curious to examine this contrivance, will see it best when the line is attached to any black object, for the threads, being whitish, are, in other cases, not so easily perceived. Shooting of the Lines. It has long been considered a curious though a diffi- cult investig-ation, to determine in what manner spiders, seeing that they are destitute of wings, transport them- selves from tree to tree, across brooks, and frequently through the air itself, without any apparent starting- point. On looking into the authors who have treated upon this subject, it is surprising how little there is to be met with that is new, even in the most recent. Their conclusions, or rather their conjectural opinions, are, however, worthy of notice ; for by unlearning error, we the more firmly establish truth. 1. One of the earliest notions upon this subject is that of Blancanus, the commentator on Aristotle, which is SPIDEKS. 87 partly adopted by Redi, byjHenricus Regius of Utrecht, by Swammerdam,* by Lehmann, and by Kirby and Spence.t "The spider's thread," says Swammerdani, "is generally made up of two or more parts, and after descending by such a thread, it ascends by one only, and is thus enabled to waft itself from one height or tree to another, even across running waters ; the thread it leaves loose behind it being driven about by the wind, and so fixed to some other body." "I placed," says Kirby, " the large garden spider (Epeira diademci) upon a stick about a foot long, set upright in a vessel containing water It let itself drop, not by a single thread, but by two, each distant from the other about the twelfth of an inch, guided, as usual, by one of its hind feet, and one apparently smaller than the other. When it had suffered itself to descend nearly to the surface of the water, it stopped short, and by some means, which I could not distinctly see, broke off, close to the spinners, the smallest thread, which still adhering by the other end to the top of the stick, floated in the air, and was so light as to be carried about by the slightest breath. On approaching a pencil to the loose end of this line, it did not adhere from mere contact. I, therefore, twisted it once or twice round the pencil, and then drew it tight. The spider, which had previously climbed to the top of the stick, im.mediately pulled at it wdth one of its feet, and finding it suffxciently tense, crept along it, strength- ening it as it proceeded by another thread, and thus , reached the pencil." We have repeatedly witnessed this occurrence, both in the fields and when spiders were placed for experi- ment, as Kirby has described ; but we very much doubt that the thread broken is ever intended as a bridge cable, or that it would have been so used in that instance, had it not been artificially fixed and accidentally found again by the spider. According to our observations, a spider never abandons, for an instant, the thread which she dispatches in quest of an attachment, but uniformly keeps * S'.vammerdam, part i. p. 24. \ lufr. vol. i. p. 415. 88 INSECT ARCHITECTURE. trying it with her feet, in order to ascertain its success. Wc are, therefore, persuaded, that when a thread is broken in the manner above described, it is because it has been spun too weak, and spiders may often be seen breaking such threads in the process of netting their webs. (J. R.) The plan, besides, as explained by these distinguished writers, would more frequently prove abortive than suc- cessful, from the cut thread not being sufficiently long. They admit, indeed, that spiders' lines are often found " a yard or two long, fastened to twigs of grass not a foot in height Here, therefore, some other pro- cess must have been used."* 2. Our celebrated English naturalist, Dr. Lister, whose treatise upon our native spiders has been the basis of every subsequent work on the subject, maintains that * ' some spiders shoot out their threads in the same manner that porcupines do their quills ;t that whereas the quills of the latter are entirely separated from their bodies , when thus shot out, the threads of the former remain fixed to their anus, as the sun's rays to its body."| A French periodical writer goes a little farther, and says, that spiders have the power of shooting out threads, and directing them at pleasure towards a determined point, judging of the distance and position of the object by some sense of which we are ignorant. § Kirby also says, that he once observed a small garden spider {Jranea reticulata) "standing midway on a long perpendicular fixed thread, and an appearance caught" his "eye, of what seemed to be the emission of threads.." " I," therefore, he adds, "moved my arm in the direction in which they apparently proceeded, and, as I had sus- pected, a floating thread attached itself to my coat, along which the spider crept. As this was connected with the spinners of the spider, it could not have been * Kirby and Spence, vol. i. Intr. p. 416. f Porcupines do not shoot out their quills, as was once generally believed. ;J: Lister, Hist. Animalia Angliae, 4to. p. 7. § Phil. Mag. ii. p. 275. SPIDERS. 89 formed " by breaking a " secondary thread."* Again, in speaking of the gossamer-spider, he says, " it first extends its thigh, shank, and foot, into a right lino, and then, elevating its abdomen till it becomes vertical, shoots its thread into the air, and flies off from its sta- tion."! Another distinguished naturalist, Mr. White of Sel- borne, in speaking of the gossamer-spider, says, " Every day in fine vreather in autumn do I see these spiders shooting out their webs, and mounting aloft : they Mill go off from the finger, if you will take them into your hand. Last summer, one alighted on my book as I was reading in the parlour ; and running to the top of the page, and shooting out a web, took its departure from thence. But what I most wondered at was, that it went off with considerable velocity in a place where no air was stirring ; and I am sure I did not assist it with my breath."t Having so often witnessed the thread set afloat in the air by spiders, we can readily conceive the way in which those 'eminent naturalists were led to suppose it to be ejected by some animal force acting like a syringe ; but as the statement can be completely disproved by experi- ment, we shall only at present ask, in the words of Swam- merdam — " how can it be possible that a thread so fine and slender should be shot out with force enough to divide and pass through the air ? — is it not rather pro- bable that the air would stop its progress, and so entangle it and fit it to perplex the spider's operations '?"§ The opinion, indeed, is equally improbable with another, sug- gested by Dr. Lister, that the spider can retract her thread within the abdomen, after it has been emitted, |j De Geer^ very justly joins Swammerdam in rejecting both of these fancies, which, in our own earlier observa- tions upon spiders, certainly struck us as plausible and * Vol. i. Intr. p. 417. f Ibid. li. p. 339. X Nat. Hist, of Selborne, vol. i. p. 327. § Book of Nature, part i. p. 25. jl Hist. Anim. Anglise, 4to. *f[ Memoiies, vol. vii. p. 189. 153 90 INSECT ARCHITECTURE. true. There can be no doubt, indeed, that the animal has a voluntary power of permitting the material to escape, or stopping it at pleasure, but this power is not projectile. 3. " There are many people," says the Abbe de la Pluche, ''who believe that the spider flies when they see her pass from branch to branch, and even from one high tree to another ; but she transports herself in this manner : she places herself upon the end of a branch, or some projecting body, and there fastens her thread ; after which, with her two hind feet, she squeezes her dugs {spinnerets), and presses out one or more threads of two or three ells in length, which she leaves to float in the air till it be fixed to some particular place."* With- out pretending to have observed this, Swammerdam says, " I can easily comprehend how spiders, without giving themselves any motion, may, by only compressing their spinnerets, force out a thread, which being driven by the wind, may serve to waft them from one place to ano- ther."f Others, proceeding upon a similar notion, give a rather different account of the matter. " The spider," says Binglcy, "fixes one end of a thread to the place where she stands, and then with her hind paws draws out several other threads from the nipples, which, being lengthened out and driven by the wind to some neigh- bouring tree or other object, are by their natural clam- miness fixed to it."t Observation gives some plausibility to the latter opi- nion, as the spider always actively uses her legs, though not to draw out the thread, but to ascertain whether it has caught upon any object. The notion of her pressing the spinneret with her feet must be a mere fancy ; at least it is not countenanced by anything which we have observed. 4. An opinion much more recondite is mentioned, if it was not started, by M. DTsjonval, that the floating of the spider's thread is electrical. *' Frogs, cats, and other * Spectacle de la Nature, vol. i. f Book of Nature, pt. i. p. 25. X Animal Biography, vol. iii. p. 475, 3rd edition. SPIDERS. 91 animals," he says, " are affected by natural electricity, and feel the change of weather ; but no other animal more than myself and my spiders." During wet and windy weather he accordingly found that they spun very short lines, " but when a spider spins a long thread, there is a certainty of fine weather for at least ten or twelve days afterwards."* A periodical writer, who signs himself Carolan,t fancies that in darting out her thread the spider emits a stream of air, or some subtle electric fluid, by which she guides it as if by magic. A living wTiter (Mr. John Murray) whose learning and skill in conducting experiments give no little weight to his o})inions, has carried these views considerably farther. " The aeronautic spider," he says, "can propel its thread both horizontally and vertically, and at all re- lative angles, in motionless air, and in an atmosphere agitated by winds ; nay more, the aerial traveller can even dart its thread, to use a nautical phrase, in the * wind's eye.' My opinion and observations are based on many hundred experiments The entire phe- nomena are electrical. When a thread is propelled in a vertical plane, it remains perpendicular to the horizontal plane, always u])right, and when others are projected at angles more or less inclined, their direction is invariably preserved; the threads never intermingle, and when a pencil of threads is propelled, it ever presents the ap- pearance of a divergent brush. These are electrical phenomena, and cannot be explained but on electrical principles." " In clear, fine weather, the air is invariably positive ; and it is precisely in such weather that the aeronautic spider makes its ascent most easily and rapidly, whether it be in summer or in winter." " When the air is weakly positive, the ascent of the spider will be difiicult, and its altitude extremely limited, and the threads pro- pelled will be but little elevated above the horizontal j)lane. When negative electricity prevails, as in cloudy * Biez, Flore des Iiisectophiles. Notes, Supp. p. 134. f Thomson's Ann. of Philosophy, vol. ill. p. 306. 92 LNSECT ARCHITECTURE. weather, or on the approach of rain, and the index of De Saussure's hygrometer rapidly advancing towards humidity, the spider is unable to ascend."* Mr. Murray had previously told us, that '*' when a stick of excited sealing-wax is brought near the thread of suspension, it is evidently repelled ; consequently, the electricity of the thread is of a negative character," while *' an excited glass tube brought near, seemed to attract the thread, and with it the aeronautic spider. "f His friend, Mr. Bowman, further describes the aerial spider as "shooting out four or five, often six or eight, ex- tremely fine webs several j^ards long, which waved in the breeze, diverging from each other like a pencil of rays." One of them "had two distinct and widely diverging fasciculi of webs," and " a line uniting them would have been at right angles to the direction of the breeze. "J Such is the chief evidence in support of the electrical theory ; but though mo have tried these experiments, we have not succeeded in verifying any one of them. The following statements of Mr. Blackwall come nearer our own observations. 5. " Having procured a small branched twig," says Mr. Blackwall, " I fixed it upright in an earthen vessel containing water, its base being immersed in the liquid, and upon it I placed several of the spiders which produce gossamer. Whenever the insects thus circumstanced were exposed to a current of air, either naturally or arti- ficially produced, they directly turned the thorax towards the quarter whence it came, even when it was so slight as scarcely to be perceptible, and elevating the abdomen, they emitted from their spinners a small portion of glu- tinous matter, which was instantly carried out in a line, consisting of four finer ones, with a velocity equal, or nearly so, to that with which the air moved, as was ap- ]:)arent from observations made on the motion of detached lines similarly exposed. The spiders, in the next place, * Loudon's Mag. of Nat. Hist,, vol. i. p. 322. f Expeiim. Researches in Nat. Hist., p. 136. X Ma-. Nat. Hist. vol. i. v- 324. SPIDERS. 93 carefully ascertained whether their lines had hecome firmly attached to any object or not, by pulling at them with the first pair of legs ; and if the result was satis- factory, after tightening them sufficiently, they made them pass to the twig ; then discharging from their spin- ners, which they applied to the spot where they stood, a little more of their liquid gum, and committing them- selves to these bridges of their own constructing, they passed over them in safety, drawing a second line after them, as a security in case the first gave way, and so effected their escape. " Such was invariably the result when spiders were placed where the air was liable to be sensibly agitated : I resolved, therefore, to put a bell-glass over them ; and in this situation they remained seventeen days, evidently unable to produce a single line by which they could quit the branch they occupied, without encountering the water at its base ; though, on the removal of the glass, they regained their liberty with as much celerity as in the instances already recorded. " This experiment, which, from want of due precau- tion, has misled so many distinguished naturalists, I have tried with several geometric spiders, and always with the same success."* Mr. Blackwall, from subsequent experiments, says ho is " confident in affirming, that in motionless air sjiiders have not the power of darting their threads even through the space of half an inch."t The following details are given in confirmation of this opinion. Mr. Blackwall observed, the 1st Oct., 1826, a little before noon, with the sun shining brightly, no wind stirring, and the ther- mometer in the shade ranging from 55^.5 to 64-, a pro- fusion of shining lines crossing each other at every angle, forming a confused net- work, covering the fields and hedges, and thickly coating his feet and ankles, as he walked across a pasture. He was more struck with the phenomenon because on the previous day a strong gale * Linn. Trans,, vol. xv. p. 456. t Mag. Nat. Hist., vol. ii. p. 397. 94 IS SECT ARCHITECTURE. of wind had blown from the south, and as gossamer is only seen in calm weather, it must have been all pro- duced within a very short time, " What more particularly arrested my attention," says Mr. Blackwall, " was the ascent of an amazing quantity of webs, of an irregular, ci)mplicated structure, resem- bling ravelled silk of the finest quality, and clearest white ; they were of various shapes and dimensions, some of the largest measuring u))wards of a yard in length, and several inches in breadth in the widest part ; while others were almost as broad as long, presenting an area of a few square inches only. " These webs, it was quickly perceived, were not formed in the air, as is generally (Dclieved, but at the earth's surface. The lines of which they were com- posed, being brought into contact by the mechanical action of gentle airs, adhered together, till, by continual additions, they were accumulated into flakes or masses of considerable magnitude, on M'hich the ascending current, occasioned by the rarefaction of the air contiguous to the heated ground, acted with so much force as to sepa- rate them from the objects to which they were attached, raising them in the atmosjjhere to a perpendicular height of at least several hundred feet. I collected a number of these webs about mid-day, as they rose ; and again in the afternoon, when the upward current had ceased, and they were falling ; but scarcely one in twenty contained a spider: though, on minute inspection, I found small winged insects, chiefly aphides, entangled in most of them. " From contemplating this unusual display of gossa- mer, my thoughts were naturally directed to the animals which produced it, and the countless myriads in which they swarmed almost created as much surprise as the sin- gular occupation that engrossed them. Apparently actu- ated by the same impulse, all were intent upon traversing the regions of air ; accordingly, after gaining tlie sum- mits of various objects, as blades of grass, stubble, rails, gates, &c., by the slow and laborious process of climb- ing, they raised themselves still higher by straightening their limbs ; and elevating the abdomen, by bringing it SPIDERS. 95 from the usual horizontal position into one almost per- pendicular, they emitted from their spinning apparatus a small quantity of the glutinous secretion with which they construct their webs. This viscous substance being drawn out by the ascending current of rarefied air into fine lines several feet in length, was carried upward, until the spiders, feeling themselves acted upon with sufficient force in that direction, quitted their hold of the objects on which they stood, and commenced their journey by mounting aloft. " Whenever the lines became inadequate to the pur- pose for which they were intended, by adhering to any fixed body, they were immediately detached from the spinners and so converted into terrestrial gossamer, by means of the last pair of legs, and the proceedings just described were repeated ; which plainly proves that these operations result from a strong desire felt by the insects to effect an ascent."* Mr. Black wall has recently read a paper (still unpublished) in the Linnean Society, con- firmatory of his opinions. 6. Vrithout going into the particulars of what agrees or disagrees in the above experiments with our own ob- servations, we shall give a brief account of what we have actually seen in our researches. (J. R.) So far as we have determined, then, all the various species of spiders, how different soever the form of their webs may be, pro- ceed in the circumstance of shooting their lines precisely alike ; but those which we have found the most manage- able in experimenting, are the small gossamer spider (^Aranea obtex/rix, Bechstein), known by its shining blackish-brown body and reddish-brown semi-transparent legs ; but particularly the long-bodied spider (^Tetrag- natha extensa^ Latr.), which varies in colour from green to brownish or grey — but has always a black line along the belly, with a silvery white or yellowish one on each side. The latter is chiefly recommended by being a very industrious and persevering spinner, while its * Linn. Trans., vol. xv. p. 453^ 96 INSECT AKCHITECTUKE. movements are easily seen, from the long cylindrical form of its body and the length of its legs. We placed the above two species with five or six others, including the garden, the domestic, and the laby- rinthic spiders, in empty wine-glasses, set in tea-saucers filled with water to prevent their escape. When they discovered, by repeated descents from the brims of the glasses, that they were thus surrounded by a wet ditch, they all set themselves to the task of throwing their silken bridges across. For this purpose they first en- deavoured to ascertain in what direction the wind blew, or rather (as the experiment was made in our study) which way any current of air set, — by elevating their arms as we have seen sailors do in a dead calm. But, as it may prove more interesting to keep to one individual, we shall first watch the proceedings of the gossamer spider. Finding no current of air on any quarter of the brim of the glass, it seemed to give up all hopes of construct- ing its bridge of escape, and placed itself in the attitude of repose ; but no sooner did we produce a stream of air, by blowing gently towards its position, than, fixing a thread to the glass, and laying hold of it with one of its feet, by way of secm*ity, it placed its body in a vertical position, Avith its spinnerets extended outwards; and immediately we had the pleasure of seeing a thread streaming out from them several feet in length, on which the little aeronaut sprung up into the air. We were convinced, from what we thus observed, that it was the double or bend of the thread which was blown into the air ; and we assigned as a reason for her previously at- taching and drawing out a thread from the glass, the wish to give the wind a. point cVappiii — something upon M'hich it might have a purchase, as a mechanic would €ay of a lever. The bend of the thread, then, on this view of the matter, would be carried out by the w^ind, — would form the point of impulsion, — and, of course, the escape bridge would be an ordinary line doubled. Such was our conclusion, which was strongly corro- SPIDERS. 97 bora ted by what we subsequently found said by M. La- treille — than whom no higher authority could be given. " When the animal," says he, " desires to cross a brook, she fixes to a tree or some other object one of the ends of her first threads, in order that the wind or a current of air may carry the other end beyond the obstacle j"* and as one end is always attached to the spinnerets, he must mean that the double of the thread flies off. In his previous publications, however, Latreille had con- tented himself with copying the statement of Dr. Lister. In order to ascertain the fact, and put an end to all doubts, we watched, with great care and minuteness, the proceedings of the long-bodied spider above men- tioned, by producing a stream of air in the same man- ner, as it perambulated the brim of the glass. It imme- diately, as the other had done, attached a thread and raised its body perpendicularly, like a tumbler standing on his hands with his head downwards ; but we looked in vain for this thread bending, as we had at first sup- posed, and going off double. Instead of this it remained tight, while another thread, or what appeared to be so, streamed off from the spinners, similar to smoke issuing through a pin-hole, sometimes in a line, and sometimes at a considerable angle, with the first, according to the current of the air, — the first thread, extended from the glass to the spinnerets, remaining all the while tight drawn in a right line. It further appeared to us, that the first thread proceeded from the pair of spinnerets nearest the head, while the floating thread came from the outer pair, — though it is possible in such minute ob- jects we may have been deceived. That the first was continuous with the second, without any perceptible joining, we ascertained in numerous instances, by catch- ing the floating line and pulling it tight, in which case the spider glides along without attaching another line to '' L'un des bouts de ces premiers fils, afin que le vent ou un courant d'air pousse laufie extiemite de lun d eux au de la de robstacle." — Diet. Classique d'Hist. Nat., vol. i. p. 510. 98 INSECT ARCHITECTURE. the glass ; but if she have to coil up the floating line to tighten it, as usually happens, she gathers it into a packet and glues the two ends tight together. Her body, while the floating line streamed out, remained quite motionless, but we distinctly saw the spinnerets not only projected, as is always done when a spider spins, but moved in the same w ay as an infant moves its lips when sucking. We cannot doubt, therefore, that this motion is intended to emit (if eject or project be deemed too strong words) the liquid material of the thread ; at the same time, we are quite certain that it cannot throw out a single inch of thread without the aid of a current of air. A long-bodied spider will thus throw out in suc- cession as many threads ijs we please, by simply blowing towards it ; but not one where there is no current, as under a bell-glass, where it may be kept till it die, without being able to construct a bridge over water of an inch long. We never observed more than one float- ing thread produced at the same time ; though other observers mention several. The probable commencement, we think, of the floating line, is by the emission of little globules of the glu- tinous material to the points of the spinnerules — perhaps it may be dropped from them, if not ejected, and the globules being carried off by the current of air, drawn out into a thread. But w^e give this as only a conjec- ture, for ^^■e could not bring a glass of suflacient power to bear upon the spinnerules at the commencement of the floating line. In subsequent experiments we found, that it was not indispensable for the spider to rest upon a solid body when producing a line, as she can do so while she is sus- pended in the air by another line. When the current of air also is strong, she will sometimes commit herself to it by swinging from the end of the line. We have even remarked this when there was scarcely a breath of air. We tried another experiment. We pressed pretty firmly upon the base of the spinnerets, so as not to injure the spider, blowing obliquely over them ; but no floating line appeared. We then touched them with a pencil SPIDEES. 99 and drew out several lines an inch or two in length, upon which we blew in order to extend them, but in this also we were unsuccessful, as they did not lengthen more than a quarter of an inch. We next traced out the re- servoirs of a garden-spider {Epeira diadema), and im- mediately taking a drop of the matter from one of them on the point of a fine needle, we directed upon it a strong current ©f air, and succeeded in blowing out a thick yellow line, as we might have done with gum-water, of about an inch and a half long. When we observed our long-bodied spider eager to throw a line by raising up its body, we brought within three inches of its spinnerets an excited stick of sealing- wax, of which it took no notice, nor did any thread extend to it, not even when brought almost to touch the spinnerets. We had the same want of success with an excited glass rod ; and indeed we had not anticipated any other result, as we have never observed that these either attract or repel the floating threads, as Mr. Murray has seen them do ; nor have we ever seen the end of a float- ing thread separated into its component threadlets and diverging like a brush, as he and Mr. Bowman describe. It may be proper to mention that Mr. Murray, in con- formity with his theory, explains the shooting of lines in a current of air by the electric state produced by motion in consequence of the mutual friction of the gaseous par- ticles. But this view of the matter does not seem to affect our statements. Nests, Webs, axd Nets of Spiders. The neatest, though the smallest spider's nest which we have seen, was constructed in the chink of a garden post, which we had cut out the previous summer in getting at the cells of a carpenter-bee. The architect was one of the larger hunting-spiders, erroneously said by some naturalists to be incapable of spinning. The nest in question was about two inches high, composed of a very close satin-like texture. There were two pa- rallel chambers placed perpendicularly, in which posi- 100 IXSECT ARCHITECTURE. tion also the inhabitant reposed there during the day, going, as we presume, only abroad to prey during the night. But the most remarkable circumstance was, that the openings (two above and two below) were so elastic, that they shut almost as closely as the boat cocoon of the Toririx Chlorava (see page 71). We observed this spider for several months, but at last it disappeared, and we took the nest out, under the notion that Jt might contain eggs ; but we found none, and therefore con- clude that it was only used as a day retreat. (J. R.) The account which Evelyn has given of these hunting- spiders is so interesting, that we must transcribe it. " Of all sorts of insects," says he, " there is none has afforded me more divertisement than the venatores (hunters), which are a sort of liqn (wolves) that have their dens in rugged walls and crevices of our houses ; a small brown and delicately-spotted kind of spiders, whose hinder legs are longer than the rest. Such I did I'requently observe at Rome, which, espying a fly at three or four yards distance, upon the balcony where I stood, would not make directly to her, but crawl under the rail, till being arrived to the antipodes, it would steal up, seldom missing its aim ; but if it chanced to want anything of being perfectly opposite, would, at first peep, immediately slide down again, — till, taking better notice, it would come the next time exactly upon the fly's back : but if this happened not to be within a competent leap, then would this insect move so softly, as the very shadow of the gnomon seemed not to be more imperceptible, unless the fly moved ; and then would the spider move also in the same proportion, keeping that just time with her motion, as if the same soul had animated both these little bodies ; and whether it were forwards, backwards, or to either side, without at all turning her body, like a well-managed horse : but if the capricious fly took wing and pitched upon another place behind our huntress, then would the spider whirl its body so nimbly about, as nothing could be imagined more swift : by which means she always kept the head towards her prey, though, to appearance, as innnoveable as if it had been SPIDERS. 101 a nail driven into the wood, till by that indiscernible pro- gress (being arrived within the sphere of her reach) she made a fatal leap, swift as lightning, upon the fly, catching him in the pole, where she never quitted hold till her belly was full, and then carried the remainder home." One feels a little sceptical, however, when he adds, '' I have beheld them instructing their young ones how to hunt, which they would sometimes discipline for not well observing ; but when any of the old ones did (as sometimes) miss a leap, they would run out of the field and hide themselves in their crannies, as ashamed, and haply not to be seen abroad for four or five hours after ; for so long have I watched the nature of this strange insect, the contemplation of whose so wonderful sagacity and address has amazed me ; nor do I find in any chase whatsoever more cunning and stratagem observed. I have found some of these spiders in my garden, when the weather, towards spring, is very hot, but they are nothing so eager in hunting as in Italy." * We have only to add to this lively narrative, that the hunting-spider, when he leaps, takes good care to pro- vide against accidental falls by always swinging himself from a good strong cable of silk, as Swammerdam cor- rectly states,! and which anybody may verify, as one of the small hunters (Salticus sceniciis), known by having its back striped with black and white like a zebra, is ver}^ common in Britain. Mr. Weston, the editor of ' Bloomfield's Remains,' falls into a very singular mistake about hunting-spiders, imagining them to be web-weaving ones which have ex- hausted their materials, and which are therefore com- pelled to hunt. In proof of this he gives an instance which fell under his own observation ! J As a contrast to the little elastic satin nest of the hunter, we may mention the largest with which we are * Evelyn's Travels in Italy. f Book of Niitiue, ])art i. }). 24. X Bloomfield's Remains, vol. ii. p. 61, fiote. 102 IKSECT ARCHITECTURE. acquainted, — that of the labyrinthic spider {Agelena lahynnthica^ Walckexaer). Our readers must often have seen this nest spread out like a broad sheet in hedges, furze, and other low bushes, and sometimes on the ground. The middle of this sheet, which is of a close texture, is swung like a sailor's hammock, by silken ropes extended all around to the higher branches ; but the whole curves upwards and backwards, sloping down to a long funnel-shaped gallery which is nearly horizontal at the entrance, but soon winds obliquely till it becomes quite perpendicular. This curved gallery is about a quarter of an inch in diameter, is much more closely woven than the sheet part of the web, and sometimes descends into a hole in the ground, though oftener into a group of crowded twigs, or a tuft of grass. Here the spider dwells secure, frequently resting with her legs extended from the entrance of the gallery, ready to spring out upon whatever insect ladiy fall into her sheet net. She herself can only be caught by getting behind her and forcing her out into the web ; but though we have often endeavoured to make her construct a nest under our eye, we have been as unsuccessful as in similar experiments with the common house spider (^Aranea domestica). (J. R.) The house spider's proceedings were long ago de- scribed by Romberg, and the account has been copied, as usual, by almost every subsequent writer. Goldsmith has, indeed, given some strange mis-statements from his own observations, and Bingley has added the original remark, that, after fixing its first thread, creeping along the wall, and joining it as it proceeds, it " darts itself to the opposite side, where the other end is to be fas- tened ! " * Romberg's spider took the more circuitous route of travelling to the opposite wall, carrying in one of the claws the end of the thread previously fixed, lest it should stick in the wrong place. This we believe to be the correct statement, for as the web is always hori- zontal, it would seldom answer to commit a floating * Animal Biography, iii. 470-1. SPIDEES. 103 thread to the wind, as is done by other species. Hom- berg's spider, after stretching as many lines by way of tvarp as it deemed sufficient between the two walls of the corner which it had chosen, proceeded to cross this in the way our weavers do in adding the woof\ with this difference, that the spider's threads were only laid on, and not interlaced.* The domestic spiders, however, in these modern daj'-s, must have forgot this mode of weaving, for none of their webs will be found to be thus regularly constructed ! ] The geometric, or net-working spiders (^Tendeuses, Latk.), are as well known in most districts as any of the preceding ; almost every bush and tree in the gardens and hedge-rows having one or more of their nets stretched out in a vertical position between adjacent branches. The common garden spider {Epeira diadem(i), and the long-bodied spider {Tetragnatha extensa), are the best known of this order. The chief care of a spider of this sort is, to form a cable of sufficient strength to bear the net she means to hang upon it ; and, after throwing out a floating line as above described, when it catches properly she doubles and redoubles it with additional threads. On trying its strength she is not contented with the test of pulling it with her legs, but drops herself down several feet from various i)oints of it, as we have often seen, swinging and bobbing with the whole weight of her bodj-. She pro- ceeds in a similar manner with the rest of the frame- work of her wheel-shaped net ; and it may be remarked that some of the ends of these lines are not simple, but in form of a Y, giving her the additional security of two attachments instead of one. In constructing the body of the net, the most remark- able circumstance is her using her limbs as a measure, to regulate the distances of her radii or whecl-spokes, and the circular meshes interweaved into them. These are consequently always proportional to the size of the spider. She often takes up her station in the centre, * Mem. de I'Acad. des Sciences pour 1707, p. 339. 104 IXSECT ARCHITECTURE. Geometric Net of Ejeira diadema. but not always, though it is so said by inaccurate writers ; for she as frequently lurks in a little chamber constructed under a leaf or other shelter at the corner of her web, ready to dart down upon whatever prey may be entan- gled in her net. The centre of the net is said also to be composed of more viscid materials than its suspensory lines, — a circumstance alleged to be proved by the former appearing under the microscope studded with globules of gum.* Wo have not been able to verify this distinction, having seen the suspensory lines as often studded in this manner as those in the centre. (J. R.) * Kirby and Spence, Intr. i. 4 19. SPIDERS. 105 Mason-Spidehs. A no less wonderful structure is composed by a sort of spiders, natives of the tropics and the south of Europe, which have been justly called mason-spiders by M. Latreille. One of these (^Mygale niclidans, Walckx.), found in the West Indies, "digs a hole in the earth obliquely downwards, about three inches in length, and one in diameter. This cavity she lines \nth a tough thick web, which, when taken out, resembles a leathern purse ; but what is most curious, this house has a door with hinges, like the operculum of some sea-shells, and herself and family, who tenant this nest, open and shut the door whenever they pass and repass. This history was told me," says Darwin, "and the nest, with its door, shown me by the late Dr. Butt, of Bath, who was some years physician in Jamaica."* The nest of a mason-spider, similar to this, has been obligingly put into our hands by Mr. Riddle, of Black- heath. It came from the West Indies, and is probably that of Latreille's clay-kneader (^Mygale cratiens), and one of the smallest of the genus. We have since seen a pair of these spiders in possession of Mr. William Mello, of Blackheath. The nest is composed of very hard argillaceous clay, deeply tinged with brown oxide of iron. It is in form of a tube, about one inch in dia- meter, between six and seven inches long, and slightly bent towards the lower extremity — appearing to have been mined into the clay rather than built. The inte- rior of the tube is lined with a uniform tapestry of silken web, of an orange- white colour, with a texture interme- diate between India paper and very fine glove leather. But the most wonderful part of this nest is its entrance, which we look upon as the perfection of insect architec- ture. A circular door, .about the size of a crown piece, slightly concave on the outside and convex within, is formed of more than a dozen layers of the same web which lines the interior, closely laid upon one another, and * Darwhi's Zoonomia, i. 253, Svo. ed. VOL. II. F 106 INSECT ARCHITECTURE. shaped so that the inner layers are the broadest, the outer being gradually less in diameter, except towards the hinge, which is about an inch long ; and in conse- quence of all the layers being united there, and pro- longed into the tube, it becomes the thickest and strongest part of the structure. The elasticity of the materials, also, gives to this hinge the remarkable peculiarity of acting like a spring, and shutting the door of the nest spontaneously. It is, besides, made to fit so accu- rately to the aperture, which is composed of similar con- centric layers of web, that it is almost impossible to dis- tinguish the joining by the most careful inspection. To gratify curiosity, the door has been opened and shut hundreds of times, without in the least destroying the power of the spring. When the door is shut, it resem- bles some of the lichens (Lecidea), or the leathery fungi, such as Pohjporus versicolor (Michej:.i), or, nearer still, the upper valve of a young oyster shell. The door of the nest, the only part seen above ground, being of a blackish-brown colour, it must be very ditficult to dis- cover. (J. R.) Another mason-spider {Mygale ctsmentaria, Latr.), found in the south of France, usually selects for her nest a place bare of grass, sloping in such a manner as to carry off the water, and of a firm soil, without rocks or small stones. She digs a gallery a foot or two in depth, and of a diameter (equal throughout) sufficient to admit of her easily passing. She lines this with a tapestry of silk glued to the walls. The door, which is circular, is constructed of many layers of earth kneaded, and bound together with silk. Externally, it is flat and rough, cor- responding to the earth around the entrance, for the pur- jDOse, no doubt, of concealment : on the inside it is con- vex, and tapestried thickly with a web of fine silk. The threads of this door-tapestry are prolonged, and strongly attached to the upper side of the entrance, forming an excellent hinge, which, when pushed open by the spider, shuts again by its own weight, without the aid of spring hinges. When the spider is at home, and her door for- cibly opened by an intruder, she pulls it strongly in- SPIDERS. 107 Nest of the Mason-Spider. A. The nestgjiut. B. The nest open. C. Tlie spider, Mygale ccemen- taria. I). The eyes magnified. E, F. Parts of the foot and claw magnified. wards, and even when half-opened often snatches it out of the hand ; but when she is foiled in this, she retreats to the bottom of her den, as her last resource.* Rossi ascertained that the female of an allied species (^Mygale saiivogesii, Latr.), found in Corsica, lived in one of these nests, with a numerous posterity. He de- stroyed one of these doors to observe whether a new one would be made, which it was : but it was fixed immoveably, without a hinge ; the spider, no doubt, for- * Mtm. Soc, d'Hist. Nat. de Paris, An. vii. r2 108 ISSECT ARCHITECTURE. tifying herself in this manner till she thought she might re-open it without danger.* "The Rev. Revett Shepherd has often noticed, in the fen ditches of Norfolk, a very large spider (the species not yet determined) which actually forms a raft for the purpose of obtaining its prey with more facility. Keeping its station upon a ball of weeds about three inches in diameter, probably held together by slight silken cords, it is wafted along the surface of the water upon this floating island, which it quits the mo- ment it sees a drowning insect. The booty thus seized it devours at leisure upon its raft, under which it retires when alarmed by any danger."!- In the spring of 1830, we found a spider on some reeds in the Croydon Canal, which agreed in appearance with Mr. Shepherd's. Among our native spiders there are several besides this one, which, not contented with a web like the rest of their congeners, take advantage of other materials to construct cells where, " hushed in grim repose," they *' expect their insect prey." The most simple of those spider-cells is constructed by a longish-bodied spider (^Aranea holosericea, Linn.), which is a little larger than the com.mon hunting spider. It rolls up a leaf of the lilac or poplar, precisely in the same manner as is done by the leaf-rolling caterpillars, upon whose cells it some- times seizes to save itself trouble, having fifst expelled, or perhaps devoured, the rightful owner. The spider, however, is not satisfied with the tapestry of the cater- pillar, but always weaves a fresh set of her own, much more close and substantial. Another spider, common in woods and copses {Epeira quadrata ?) weaves together a great number of leaves to form a dwelling for herself, and in front of it she spreads her toils for entrapping the unwary insects which stray thither. These, as soon as caught, are dragged into her '■'' Mem. Soc. d'Hist. Nat. de Paris, An. vii. p. 125, and Latreille, Hist. Nat. Geuer. viii. p. 163. f Kiiby and Spence, Intr. i. 425. SPIDERS. 109 den, and stored up for a time of scarcity. Here also her egrgs are deposited and hatched in safety. When the cokl weather ajiproaches, and the leaves of her edifice wither, she abandons it for the more secm'e shelter of a hollow tree, where she soon dies ; but the continuation of the species depends upon eggs, deposited in the nest before winter, and remaining to be hatched with the warmth of the ensuing summer. The spider's den of united leaves, however, which has just been described, is not always useless when withered and deserted ; for the dormouse usually selects it as a ready-made roof for its nest of dried grass. That those old spiders' dens are not accidentally chosen by the mouse, appears from the fact, that out of about a dozen mouse- nests of this sort found during winter in a copse between Lewisham and Bromley, Kent, every second or third one was furnished with such a roof. (J. R.) Diving Water-Spider. Though spiders require atmospheric air for respiration, yet one species well known to naturalists is aquatic in its habits, and lives not only upon the surface but below the surface of the water, contriving to carry down with it a sufficiency of air for the support of life during a considerable period of time. Its subaqueous nest is in fact a sort of diving-bell, and constitutes a secure and most ingenious habitation. This spider does not like stagnant water, but prefers slow running streams, canals, and ditches, where she may often be seen, in the vici- nity of London and elsewhere, living in her diving-bell, which shines through the water like a little globe of silver : her singular economy was first, we believe, de- scribed by Clerck,* L. M. de Lignac,t and De Geer. '' The shining appearance," says Clerck, " proceeds either from an inflated globule surrounding the abdomen, or from the space between the body and the water. The * Aranei Suecici, Stockholm, 1757. f Mem. des Aiaign. Aquat., 12mo. Paris, 1799. 110 INSECT ARCHITECTURE. spider, when wishing to inhale the air, rises to the sur- face, with its body still submersed, and only the part containing the spinneret rising just to the surface, when it briskly opens and moves its ibur teats. A thick coat of hair keeps the water from approaching or wetting the abdomen. It comes up for air about four times an hour or oftener, though I have good reason to suppose it can continue without it for several days together. "I found in the middle of May one male and ten. females, which I put into a glass filled with water, where they lived together very quietly for eight days. I put some duck- weed {Lemna^ into the glass to afford them shelter, and the females began to stretch diagonal threads in a confused manner from it to the sides of the glass about half way down. Each of the females afterwards fixed a close bag to the edge of the glass, from which the water was expelled by the air from the spinneret, and thus a cell was formed capable of containing the whole animal. Here they remained quietly, with their abdomens in their cells, and their bodies still plunged in the water ; and in a short time brimston-coloured bags of eggs appeared in each cell, filling it about a fourth part. On the 7th of July several young ones swam out from one of the bags. All this time the old ones had nothing to eat, and yet they never attacked one another as other spiders would have been apt to do."* *' These spiders," says De Geer, "spin in the water a cell of strong, closely woven, white silk in the form of half the shell of a pigeon's egg, or like a diving-bell. This is sometimes left partly above water, but at others is entirely submersed, and is always attached to the ob- jects near it by a great number of irregular threads. It is closed all round, but has a large opening below, which, however, I found closed on the loth of December, and the spider living quietly within, with her head down- wards. I made a rent in this cell, and expelled the air, upon which the spider came out ; yet though she ap- peared to have been laid up for three months in her * Cleick, Aranei Suecici, cap. viii. SPIDERS. Ill winter quarters, she greedily seized upon an insect and sucked it. I also found that the male as well as the female constructs a similar subaqueous cell, and during summer no less than in winter."* We have recently kept one of these spiders for several months in a glass of water, where it built a cell half under water, in which it laid its eggs. Cleanliness of Spidebs. When we look at the viscid material with which spiders construct their lines and webs, and at the rough, hairy covering (with a few exceptions) of their bodies, we might conclude, that they would be always stuck over with fragments of the minute fibres which thoy produce. This, indeed, must often happen, did they not take careful precautions to avoid it ; for we have observed that they seldom, if ever, leave a thread to float at random, except when they wish to form a bridge. When a spider drops along a line, for instance, in order to ascertain the strength of her web, or the nature of the place below her, she invariably, when she re-ascends, coils it up into a little ball, and throws it away. Her 'J'riple-clawed foot of a Spider, magnified. claws are admirably adapted for this purpose, as well as for walking along the lines, as may be readily seen by a magnifying glass. There are three claws, one of which acts as a thumb, * De Geer, jMem. des Insectes, vii. 312. 112 IXSECT ARCHITECTURE. the others being toothed like a comb, for gliding along the lines. This structure, however, unfits it to walk, as flies can do, upon any upright polished surface like glass ; although the contrary* is erroneously asserted by the Abbe de la Pluche. Before she can do so, she is obliged to construct a ladder of ropes, as Mr. Blackwall remarks,! by elevating her spinneret as high as she can, and laying down a step upon which she stands to form a second ; and so on, as any one may try by placing a spider at the bottom of a very clean wine glass. The hairs of the legs, however, are always catching bits of web and particles of dust ; but these are not suffered to remain long. Most people may have re- marked that the house-fly is ever and anon brushing its feet upon one another to rub off the dust, though we have not seen it remarked in authors that spiders are equally assiduous in keeping themselves clean. They have, besides, a very efficient instrument in their man- dibles or jaws, which, like their claws, are furnished with teeth ; and a spider which appears to a careless observer as resting idly, in nine cases out of ten will be found slowly combing her legs with her mandibles, beginning as high as possible on the thigh, and passing down to the claws. The flue which she thus combs off is regu- larly tossed away. With respect to the house-spider {A. domestica), we are told in books, that " she from time to time clears away the dust from her web, and sweeps the whole by giving it a shake with her paw, so nicely proportioning the force of her blow, that she never breaks any thing."$ That spiders may be seen shaking their webs in this manner, we readily admit ; though it is not, we imagine, to clear them of dust, but to ascertain whether they are sufficiently sound and strong. We recently witnessed a more laborious process of cleaning a web than merely shaking it. On coming down the Maine by the steam-boat from Frankfort, in * Spectacle de la Nature, i. 58. f Linn. Trans, vol. xv. X Spectacle de la Nature, i. p. 61. SPIDERS. 113 August 1829, we observed the geometric-net of a conic- spider (Epeira conica, Walck.) on the framework of the deck, and as it was covered with flakes of soot from the smoke of the engine, we were surprised to see a spider at work on it ; for, in order to be useful, this sort of net must be clean. Upon observing it a little closely, however, w^e perceived that she was not constructing a net, but dressing up an old one ; though not, we must think, to save trouble, so much as an expenditure of material. Some of the lines she dexterously stripped of the flakes of soot adhering to them ; but in the greater number, finding that she could not get them sufficiently clean, she broke them quite off', bundled them up, and tossed them over. We counted five of these packets of rubbish which she thus threw away, though there must have been many more, as it was some time before we discovered the manoeuvre, the packets being so small as not to be readily perceived, except when placed between the eye and the light. When she had cleared off" all the sooted lines, she began to replace them in the usual way ; but the arrival of the l)oat at Mentz put an end to our observations. (J. R.) Bloomfield, the poet, having observed the disappearance of these bits of ravelled web, imagined that the spider swallowed them ; and even says that he observed a garden spider moisten the pellets before swallowing them l* Dr. Lister, as we have already seen, thought the spider retracted the threads within the abdomen. * Remains, ii. 62-5. It is a remarkable fact, as recorded from personal observation by Mr. Bell (British Reptiles), that the toad swallows the cuticle detached from its body during the moult which it undergoes. f3 114 IXSECT ARCHITECTURE. CHAPTEH XIX. Structures of Gall- Flies and Aphides. Many of the processes which we have detailed bear some resemblance to our own operations of" building with materials cemented together ; but we shall now turn our attention to a class of insect-architects, who cannot, so far as we know, be matched in prospective skill by any of the higher orders of animals. We refer to the numerous family which have received the name of gall- flies, — a family which, as yet, is very imperfectly under- stood, their economy being no less difficult to trace, than their species is to arrange in the established systems of classification ; though the latter has been recently much improved by Mr. Westwood. Small berry-shaped galls of the oak leaf, produced by Cynips quercusfuliif GALL-FLIES. 116 One of the most simple and very common instances of the nests constructed by gall-insects, may be found in abundance during- the summer, on the leaves of the rose-tree, the oak, the poplar, the willow (Salix vimi- nalis}, and many other trees, in the globular form of a berry, about the size of a currant, and usually of a green colour, tinged with red, like a ripe Alban or Bal- timore apple. When this pseudo-apple in miniature is cut into, it is found to be fresh, firm, juicy, and hollow in the centre, where there is either an egg or a grub safely lodged, and protected from all ordinary accidents. Within this hollow ball the egg is hatched, and the grub feeds securely on its substance, till it prepares for its winter sleep, before changing into a gall-fly (Cy nips') in the ensuing summer. There is a mystery as to the manner in which this gall-fly contrives to produce the hollow miniature-apples, each enclosing one of her eggs ; and the doubts attendant upon the subject cannot, so far as our present knowledge extends, be solved, except by plausible conjecture. Our earlier naturalists were of opinion that it was the grub which produced the galls, by eating, when newly hatched, through the cuticle of the leaf, and remaining till the juices flowing from the wound enveloped it, and acquired consistence by exposure to the air. This opinion, however, plausible as it appeared to be, was at once disproved by finding nnhatched eggs on opening the galls. There can be no doubt, indeed, that the mother gall-fly makes a hole in the plant for the purpose of depositing her eggs. She is furnished with an admirable ovipositor for that express purpose, and Swammerdam actually saw a gall-fly thus depositing her eggs, and we have recently witnessed the same in several instances. In some of these insects the ovipositor is conspicuously long, even when the insect is at rest ; but in others, not above a line or two of it is visible, till the belly of the insect be gently pressed. When this is done to the fly that produces the currant-gall of the oak, the ovipositor may be seen issuing from a sheath in form of a small 116 IXSECT ARCHITECTUKE. curved needle, of a chesnut-brown colour, and of a homy substance, and three times as long as it at first appeared. Ovipositor of gall-fly, greatly magniOed* What is most remarkable in this ovipositor is, that it is much longer than the whole body of the insect, in whose belly it is lodged in a sheath, and, from its horny nature, it cannot be either shortened or lengthened. It is on this account that it is bent into the same curve as the body of the insect. The mechanism by which this is effected is similar to that of the tongue of the wood- peckers {Picidcs}, which, though rather short, can be darted out far beyond the beak, by means of a forked bone at the root of the tongue, which is thin and rolled up like the spring of a watch. The base of the ovipo- sitor of the gall-fly is, in a similar way, placed near the anus, runs along the curvature of the back, makes a turn at the breast, and then, following the curve of the belly, api:>ears again near where it originates. We copy from R'-aumur his accurate sketch of this remarkable structure. With this instrument the mother gall-fly pierces the part of a plant which she selects, and, according to our older naturalists, " ejects into the cavity a drop of her corroding liquor, and immediately lays an e^g or more there ; the circulation of the sap being thus interrupted, and thrown, by the poison, into a fermentation that bums the contiguous parts and changes the natural GALL-FLIES. 117 Gall-fly, and mechanism of ovipositor, greatly magnified. colour. The sap, turned from its proper channel, cx- travasates and flows round the eggs, ^hile its sui-lace is dried by the external air, and hardens into a vaulted form."* Kirby and Spence tell us, that the parent fly introduces her egg *' into a puncture made by her curious spiral sting, and in a few hours it becomes surrounded with a fleshy chamber. '"f M. Virey says, the gall tubercle is produced by irritation, in the same way as an inflamed tumor in an animal body, by the swelling of the ceHular tissue and the flow of liquid matter, which changes the organization, and alters the natural external form. J This seems to be the received doctrine at pre- sent in France, § Sprcngel, speaking of the rose-willow, says, the insect in spring deposits its eggs in the leaf buds. " The new stimulus attracts the sap, — the type of the part becomes * Spectacle de la Nature, i. 119. t Iiitrod. ii. 449. ^ Hist, des Moeurs et de rinstlnct, vol. ii. ■6 Entoinologie par R. A. E. page 242. Paris, 1826. 118 INSECT ARCHITECTURE. changed, and from the prevailing acidity of the animal juice, it happens, that in the rose and stock-shaped leaves which are pushed out, a red instead of a green colour is evolved."* Without pretending positively to state facts which are, perhaps, beyond human penetration, we may view the process in a rather different light. (J. R.) Following the analogy of what is knoum to occur in the case of the saw-flies (see page 150), after the gall-fly has made a puncture and pushed her egg into the hole, we may suppose that she covers it over with some adhesive gluten or gum, or the egg itself, as is usual among moths, &c;, may be coated over with such a gluten. In either of these two cases, the gluten will prevent the sap that flows through the puncture from being scattered over the leaf and wasted ; and the sap, being thus confined to the space occupied by the eggs, will expand and force outwards the pellicle of gluten that confines it, till be- coming thickened by evaporation and exposure to the air, it at length shuts up the puncture, stops the further escape of the sap, and the process is completed. This explanation will completely account for the globular form of the galls alluded to ; that is, supposing the egg of the gall-fly to be globular, and covered or coated with a pellicle of gluten of uniform thickness, and consequently 0])posing uniform resistance, or rather uniform expan- sibility, to the sap pressing from within. It will also account for the remarkable uniformity in the size of the gall apples ; for the punctures and the eggs being uniform in size, and the gluten, by supposition, uniform in quan- tity, no more than the same quantity of sap can escape in such circumstances. But though this explanation appears to be plausible, it is confessedly conjectural ; for though Swammerdam de- tected a gall-fly in the act of depositing her eggs, he did not attend to this circumstance ; and in the instances which we have observed, some unlucky accident always prevented us from following up our observations. The * Elements of the Philosophy of Plants, Eng. Trans., p. 285. GALL-rLlES. 119 indefatigable Reaumur, on one occasion, thought he would make sure of tracing the steps of the process in the case of the gall-fly which produces the substance called hedeguar on the wild rose-tree, and to which we shall presently advert. His plan was to enclose in a box, in which a brood of flies had just been produced from a bedeguar, a living branch from a wild rose-tree ; but, to his great disappointment, no eggs were laid, and no bedeguar formed. Upon further investigation, he dis- covered that the brood of flies produced from the bede- guar were not the genuine bedeguar insects at ail, but one of the parasite ichneumons (Callimone Bedeguaris, Stephens), which had surreptitiously deposited their eggs there, in order to supply their young with the bedeguar grubs, all of which they appeared to have Bedeguar Gall of tlie Rose, produced by Cynips Ros'), the natural capacity of the stomach, which, according to Blamenbach, contains about three pints,* is very much Blumenbach, Physiol., s. xxlii. 160 RAVAGES OF INSECTS, View of the upper side. "View of the under side* JB 3^ 33J I): r A,B,C,The ceso- phagus and its ap- pendaj^es. D, E, The sto- mach ; — a pair of muscles wind spi- rally round it, and . -^ by tiieir contraction V\^- squeeze the digested food into the intes- tines. E, F, Tlie first large intestine. F, G, the second, G, II, the third. I, I, The biliary tubes, or bile ves- sels. E, 'f- ■Q m f H h: Viscera of the Cossus. CATERPILLARS. A, Caterpillar of Vanessa urticse magnified, a — li, the intestines of the same, a, the gullet, b b b b, pulmonary tubes, c c, ligament of the stomach, d d d d, transparent rings of the same, e e,/, g g, h h, biliary vessels, i k, the rectum. H $ 162 P.AVAGES OF IXSECTS. B d Intestinal cnnais of the caterpillar, pupa, and butterfly. A. Caterpillar, a, the CESophajjus. h, the stomach, c d, the two lar^je intestines. B. Pup;i two days old. a, the oesophagus. 6, the stomach, c rf, the two large intestines. C. Pupa t'rijht days old. «, dilation of the oesophagus, forming the crop or hi)ney-stumach. D. I'upa immediately before its transformation, a, the honey stomach become a lateral appendage of the CBsophagus. /;, the stomach. c d, the large intestines. E. Butterfly, a, honey-stomach, h, the digesting stomach, c d, the large intestines, become very long. enlarged. This was peculiarly the case -with Tarare, an Italian juggler, who, i'rom swallowing flints, whole bas- kets of fruit, &c., seems to have enlarged the capacity of his stomach so as to render his appetite insatiable. M. Tessier, of the Infirmary at Versailles, where Tarare died of consumption, found on examination that his sto- mach was prodigiously distended.* The same must have been the case with the French prisoner at Liverpool, who, on the testimony of Dr. Cochrane, consumed, in one day, sixteen pounds of raw meat and tallow candles, besides five bottles of porter.f The mandibles of caterpillars, which do not act per- * M. Percy, in Rapport d' Institute Nationelle. t Med. and Pliys. Jouin., iii. 209. gATERPILLArvS. 163 pcndicularly like the jaws of quadrupeds, but horizontally, are for the most part very sharp and strong, being of a hard, horny substance, and moved by powerful muscles. They are, for the most part, slightly bent in the form of a reaping-hook ; having the concavity indented with tooth-shaped projections, formed out of the substance of the jaw, and not socketed as the teeth of quadrupeds. These are made to meet like the blades of a pair of pincers ; and in some cases they both chop and grind the food.* Besides these there is a yjair of jav>s {inaxillcc') placed on each side of the middle portion of the under lip ; and from their being of a softer substance they seem to be more for the purpose of retaining the food than for mastication. This formidable apparatus for masti- cating {Irophi) is well adapted to supply the large de- mands of the capacious stomachs of larvae ; and when we consider that all of them are employed in eating at least for ten or twelve hours in the day, and a gi'cat number during the night, we need not wonder at their extensive ravages upon the substances on which they feed. It may be interesting, however, to give a few examples of their destructiveness ; and with this view it will be con- venient to consider them under the three popular names of caterpillars, grubs, and maggots. Caterpillaks. The ravages of caterpillars are amongst the most con- spicuous of insect depredations, in consequence of their being committed upon the leaves of trees, bushes, and plants, which are often stripped as bare as in winter. Even the smaller sorts of caterpillars become, from their multiplicity, sometimes as destructive as those which are of considerable magnitude. During the summer of 1S27 we were told that an extraordinary blight had suddenly destroyed the leaves of all the trees in Oak of Honour Wood, Kent. On going thither, we found the report had been little exaggerated ; for though it was "in the leafy month of June," there was scarcely a leaf to be * Cuvier, Auat. Com., iii. 322. 164 RAVAGES OF INSECTS, seen on the oak-ti'ees. which constitute the greater por- tion of" the wood. But we were rather sur[n*ised when we discovered, on examination, that this extensive de- struction had been effected by one of the small soli- tary leaf-rollers (^Tortrix vindana, Haworth) ; for one of this sort seldom consumes more than four or five leaves, if so much, durino; its existence. The number, therefore, of these caterpillars must have been almost be- yond conception ; and that of the moths, the previous year, must also have been very great : for the mother moth only lays from fifty to a hundred eggs, which are glued to an oak branch, and remain during the winter. It is remarkable that in this wood during the two follow- ing summers these caterpillars did not abound. (J. R.) Instances like this, however, from solitary species, are, Ravages of the bufF-tip caferpillar {Pi/T^ra bucphala). a, the full- grown caterpillar, b, the moih. c '•, a line of young caterpillars, ad- vancing along a leaf and devouring it hilf through as they march rf, the CKjis. CATERPILLARS. 165 we believe, less common than those of the ravages of gregarious caterpillars. In 1826, colonies of the buff-tip (^Pi/gesra bucephala^ Ochsenheim) were in some parts of the country very abundant. We remarked them par- ticularly at llarrow-on-the-IIill, and at Compton-Basset in Wiltshire. From their feeding in company, they strip a tree, branch after branch, scarcely leaving the fragment of a leaf, till a great portion of it is completely bare. Some of the magnificent beeches in Compton Park, from this cause, appeared with the one-half of their branches leafless and naked, while the other half was untouched. Besides the beech, these caterpillai-s feed on the oak, the lime, the hazel, the elm, and the willow. When newly hatched they may be readily discovered, from their sin- gular manner of marshalling themselves, like a file of soldiers, on a single leaf, only eating it half through ; and in their more advanced stage, their gaudy stripes of yellow and black render them very conspicuous on the branches v/hich they have nearly stripped bare. The cuckoo feeds as greedily upon them as they do on leaves, and may be seen early in the morning perched in the midst of their colonies, and devouring them by dozens. (J. R.) Those caterpillars which feed upon fruit-trees and hedge shrubs are still more likely to attract attention ; since, when any of these are abundant, it is scarcely pos- sible to stir out of doors without observing them. Thus, in the suburbs of London, in the summer of 1829, not only the orchards and gardens, but every hedge, swarmed with the lackey caterpillars {C/isiocampa nensfn'a), which are what naturalists term polyphagous feeders, that is, they do not confine themselves to a particular sort of tree, but relish a great number. The hawthorn, the blackthorn, and the oak, hov.ever, seem to be most to their taste ; while they are rare on the willow, and we have never observed them on the poplar or the elder. Another of what may be api)ropriately termed the en- camping caterpillars, of a much smaller size, and of a different genus, is the small ermine ( Yponomeuta pa- della), which does not, besides, feed quite so indiscrimi- nately ; but when the bird-cherry {Prwnis padiis), its 166 KAVAGES OF ISTSECTS. peculiar food, is not to be; had, it will put up with black- thorn, plum-tree, hawthorn, and almost any sort of orchard fniit-trce. With respect to such caterpillars as feed on different plants, Reaumur and De Geer make the singular remark, that in most cases they would only eat the sort of plant upon which they were originally hatched.* We verified this, in the case of the cater- pillar in question, upon two different nests which we took, in 1806, from the bird-cherry at Crawfordland, in Ayr- shire. Upon bringing these to Kilmarnock, we could not readily supply them with the leaves of this tree ; and having then only a slight acquaintance v.ith the habits of insects, and imagining they would eat any soi't of leaf, we tried them with almost everything green in the vicinity Ei.campinent of the caterpillar of the small ermine {YponomevXa padellu) on the Siberian crab. * De Geer, Mem. i. 319. CATERPILLARS. 167 of the town ; but they refused to touch any which we ofi'ered them. After they had flisted several days, wo at length procured some fresh branches of the bird-cheny, with which they gorged themselves so that most of them died. Last summer (1829) we again tried a colony of these caterpillars, found on a seedling plum-tree at Lee, in Kent, with blackthorn, hawthorn, and many other leaves, and even with those of the bird-cherry ; but they would touch nothing except the seedling plum, refusing the grafted varieties. (J. R.) A circumstance not a little remarkable in so very nice a feeder is, that in some cases the mother moth will de- posit her eggs upon trees not of indigenous growth, and not even of the same genus with her usual favourites. Thus, in 1825, the cherry-apple, or Siberian crab (Pt/riis pninijoUa, Willdenow), so commonly grown in the suburbs of London, swarmed with them. On a single tree at Islington we counted above twenty nests, each of \A hich would contain from fifty to a hundred cater- pillars ; and though these do not grow thicker than a crow-quill, so many of them scarcely left a leaf unde- voured, and, of course, the fruit, which showed abun- dantly in spring, never came to maturity. The summer following they were still more abundant on the hawthoi-n hedges, particularly near the Thames, by Battersca and Richmond. Since then we have only seen them spar- ingly ; and last summer we could only find the single nest upon which we tried the preceding experiment. (J. R.) This present spring (1830) they have again appeared in millions on the hedges. Reaumur says that in some years they were exceed- ingly destructive to his apple-trees, though they did not touch his pears, plums, or apricots,* which agrees precisely with our own remarks. We are well aware that there are several species of the small ermines, all similar in manners, such as the one which feeds on the spindle-tree {Euonijmus), and produces the prettiest moth of the genus ( Yponomeiita Euomjmelld) ; but our preceding remarks all apply to one species. * Reaumur, Mem. ii. 198. 168 RAVAGES OF INSECTS. In 1829 we remarked a very extraordinary number of webs of some similar caterpillar, of which we did not ascertain the species, on the willows in Holland and the Netherlands^ from Amsterdam to Ostend. In some districts, particularly near Bruges and Rotterdam, the leaves were literally stripped from whole rows of trees ; while other rows, at no considerable distance, were entirely free from their ravages. A foreign naturalist, quoted by Harris in his Aurelian, says, that the caterpillar of the Camberwell beauty ( Vanessa Antiopa), which feeds gregariously on the willow, sometimes defoliates the trees of a whole district in the Low Countries; but the ravages observed by us were evidently made by the caterpillars of some small moth. (J. R.) None of the preceding details, however, appear so striking as what is recorded of the brown-tail moth (^Pirthesia aurifluci) by Mr. W. Curtis,* whose multi- tudinous colonies spread great alarm over the country in the summer of 1782. This alarm was much increased by the exaggeration and ignorant details which ibund their way into the newspapers. The actual numbers of these caterpillars must have been immense, since Curtis says, "in many of the parishes near London subscrip- tions have been opened, and the poor people emplo^^ed to cut off the webs at one shilling per bushel, which have been burnt under the inspection of the church- wardens, overseers, or beadle of the parish : at the first onset of this business fourscore bushels, as T was most credibly informed, were collected in one day in the parish of Clapham." It is not, therefore, very much to be wondered at, that the ignorant, who are so prone to become the victim of groundless fears, should have taken serious alarm on having so unusual a phenomenon forced upon their attention. Some alarmists accordingly asserted that the caterpillars "were the usual presage of the plague ;" and others that they not only presaged it, but would actually cause it, for "their numbers were * Curtis, Hist, of Brown-tail Moth, 4to. London, 1782. CATERPILLARS. 169 great enough to render the air pestilential," while, to add to the mischief, "they would destroy every kind of vegetation, and starve the cattle in the fields." " Almost every one," adds Curtis, " ignorant of their history, was under the greatest apprehensions concern- ing them ; so that even prayers were offered up in some churches to deliver the comitry from the apprehended approaching calamity." It seems to have been either the same caterpillar, or one very nearly allied to it, probably that of the golden- tail (Porthesla C/iri/sonhoea), which in 1731-2 pro- duced a similar alarm in France. Reaumur, on going from Paris to Tours, in September 1730, found every oak, great and small, literally swarming with them, and their leaves parched and brown as if some burning wind had passed over them ; for when newly hatched, like the young buff-tips, they only eat one of the membranes of the leaf, and of course the other withers away. These infant legions, under the shelter of their warm nests, survived the winter in such numbers, that they threatened the destruction not only of the fruit-trees, but of the forests, — every tree, as Reaumur says, being overrun with them. The Parliament of Paris thought that ravages so widely extended loudly called for their interference, and they accordingly issued an edict, to compel the people to uncaterpillar (decheniller) the trees ; which Reaumur ridiculed as impracticable, at least in the forests. About the middle of May, however, a succession of cold rains produced so much mortality among the caterpillars, that the people were hajipily released from the edict ; for it soon became difficult to find a single individual of the species.* In the same way the cold rains, during the summer of 1829, seem to have nearly annihilated the lackeys, which in the early part of the summer swarmed on every hedge around London. The ignorance dis- played in France at the time in question, was not inferior to that recorded by Curtis ; for the French journalists gravely asserted that part of the caterpillars were pro- * Rcaumuv, ii. p. 137. 170 EAYAGES OF INSECTS. duced by spiders ; and that these spiders, and not the caterpillars, constructed the webs of the slime of snails, which they were said to have been seen collecting for the purpose ! " Verily," exclaims Reaumur, " there is more ignorance in our age than one might believe." It is justly remarked by Curtis, that the caterpillar of the brown-tail moth is not so limited a feeder as some, nor so indiscriminate as others ; but that it always con- hnes itself to trees or shruijs, and is never found on her- baceous plants, whose low growth v.ould seldom supply a suitable foundation for its web. Hence the absurdity of supposing it would attack the herbage of the field, and produce a famine among cattle. Curtis says, it is found on the " hawthorn most plentifully, oak the same, elm very plentifully, most fruit-trees tlie same, black-thorn plentifully, rose-trees the same, bramble the same, on the willow and poplar scarce. None have been noticed on the elder, walnut, ash, fir, or herbaceous plants. With respect to fruit-trees the injuries they sustain are most serious, as, in destroying the blossoms as yet in the bud, they also destroy the fruit in embryo ; the owners of orchards, therefore, have great reason to be alarmed." The sudden appearance of great numbers of these caterpillars in particular years, and their scarcity in others, is in some degree explained by a fact stated by Mr. Salisbury. "A gentleman of Chelsea," he says, " has informed me that he once took a nest of moths and bred them ; that some of the eggs came the first year, some the second, and others of the same nest .did not hatch till the third season."* We reared, during 1829, several nests both of the brown-tails and of the golden- tails, and a number of the females deposited their eggs in our nurse-cages ; but, contrary to the experiment just quoted, all of these were hatched during the same autumn. (J. R.) Tlie difi'erence of temperature and moisture in particular seasons may produce this diversity. An alarm, similar to those we have recorded, was pro- duced in France in 1735 by the green-striped caterpillars Salisbury, Hints on Orchards, p. 53. CATERPILLARS. 171 oF a moth very common in Britain, called by collectors, from a mark on its upper wings, the Y, or more properly the y moth {Plusia Gamma, Ochs.)- Though ranked in some classifications amongst the nocturnal moths, it flies chiefly by day, and may be seen in Battersea-fields, or other moist meadows, flitting from herb to herb and flower to flower, in short and low flights ; for it seldom soars higher than the tallest grass-stem, or the crimson flower-heads of the knap-weed, upon whose honey it sometimes regales, remaining on the wing all the while it is sipping it. During the cold rainy summer of 1829 it was almost the only moth which appeared plentiful. (J. R.) At least two broods seem to be produced dur- ing the season ; which may account for its being found from May till the setting-in of the winter frosts. Notwithstanding its being so plentiful, however, we have not heard of its having ever been so destructive here as in France, where, as usual, the most improbable causes were assigned for its increase. " In some places," says Reaumur, " they assured me they had seen an old soldier throw the spell ; and in other places an ugly and mis- chievous old woman had wrought all the evil."* These supposed supernatural agents, however, must have been either very numerous or very active to fill, not only the gardens, but every field, with legions of those caterpil- lars, which devoured almost every green thing, and left only the stalks as monuments of their devastation. The alarm proceeded farther, for it began to be whispered that they were poisonous; and many were in consequence afraid to touch soups or salads. Reaumur thought it in- cumbent on him to refute this notion at some length ; but we cannot accept his doctrine as very palatable, when he tells us that few dishes of soup or salad are ever prepared without containing caterpillars, and yet all the world are not poisoned thereby, any more than by eating oysters or viper broth. He endeavoured also to account by cal- culation for their excess, from the data of the female moth laying about four hundred eggs. Now, if there * Reaumur, ii. 336. 172 KA VAGES OF IK SECTS. Transformations of the "y moth {Pltisia Gamma), a, the egg, greatly magnified, on a morsel of leaf, b, the egg on a leaf, natural size, c, the larva, d, the pupa, e, the moth, were only twenty caterpillars distributed in a garden, and all lived through the winter, and became moths in the succeeding May, the eggs laid by these, if" all fertile, would produce 800,000, a number much more than suffi- cient to effect great destruction.* Did not Providence, therefore, put causes in operation to keep them in due bounds, the caterpillars of this moth alone, leaving out of consideration the 2000 other British species, would soon destroy more than half of our vegetation. The caterpillar just mentioned, amongst other pot- herbs, attacks coleworts and cabbage ; and may sometimes be found there along with another, not uncommon, but seldom very destructive, called by collectors the burnished brass (Plusia dirysitis)^ M'hich differs little from the caterpillar of the y moth, except in being of a brighter green. Another, called the old gentlewoman (Mames- tra b?'assica?, Treitsche), is so destructive to cabbages in Germany, that the gardeners gather whole basketsful * Reaumur, ii. 337. CATERPILLARS. 173 and luiiy them ; but as Rosel remarks, they might as well endeavour to kill a ci'ab by covering it with sea- water, for it is natural to them to burrow under ground when they change into chrysalides.* We have seen this caterpillar, as well as that of the brown-eye (^Mamestra oleraceci), do considerable damage in Wiltshire, but nothing to what is reported of it in Germany. The leaves of cabbages, cauliflower, brocoli, cole- worts, and turnips, are frequently devoured to a more considerable extent by the sub-gregarious caterpillars of the white butterflies (Pontia brassicce, P. napi, &c.). From the great multiplicity of the butterflies, indeed, and from there being two broods in the year, we have reason to wonder that their ravages are not more extensive. But we have remarked that they seem more partial to wild than cultivated plants ; for we have seen, near Islington, the oleraceous weeds, such as rape {Brassica napus), overrun with them in the very same fields with cultivated cabbages, which were not touched (J. R.) ; so that the caterpillars are not aUvays so injurious as we might at first suppose, since in this case they tend to keep down the weeds, while the birds and the ichneumon flies keep them in check by making prey of them. The gregarious caterpillars of an allied species, called the black-veined white butterfly (Pieris Cratc&gi, Stephens), is in some seasons and districts no less de- structive to orchards and hawthorn hedges than the pre- ceding ones are to the kitchen-garden. Salisbury, who wrote at Chelsea in 1815, says it "commits great de- struction every spring, and not only to the apple-trees, but other kinds of fruits. "f Mr. Stephens, writing in 1827, says, " In June, 1810, I saw it in plenty at Coombe Wood, and in the following year I captured several at Muswell-hill, since which time I have not seen any at large. "J JMr. Haworth also says, "it has not of late years been seen at Chelsea, where it formerly abounded." • Rosel, Inseckten, i. iv. 170. f Hints on Orchards, p. 56. X Illustrations, i. Haustellata, 27. 174 KAVAGES OF INSECTS. We have never met with it at all. According to Salis- bury the female butterfly lays her eggs near the extremity of an old rather than a young branch, and covers them v»'ith a coating of gluten, which is both impervious to moisture and impenetrable (this we doubt) to the bills of birds. " In this state," he adds, " we have instances of their remaining without losing their vitality for several years, until a favourable opportunity of their being- brought into existence arrives."* The caterpillars, M'hich are at first black and hairy, live in common in a silken tent. They become subsequently striped with reddish brown, and disperse over the trees. This cater- pillar and its butterfly are figured in a subsequent page. Our gooseberry and red-currant bushes are very fre- quently despoiled of their leaves, both by the speckled caterpillar of the magpie moth {Abraxas giossnlariata), and by what Reaumur terms the pseudo-caterpillars of one of the saw-flies {Nemaiiis Hibesit, ST£PHE^s). The latter insect has a flat yellow body and four pellucid wings, the two outer ones marked with brown on the edge. In April it issues from the pupa, which has lain under ground from the preceding September. The female of the gooseberry saw-fly does not, like some of the family, cut a groove in the branch to deposit her eggs; — "of what use, then,'' asks Reaumur, "is her ovipositor saw '?"t In order to satisfy himself on this point, he introduced a pair of the flics under a bell-glass along with a branch bent from a red-currant bush, that he might watch the process. The female immediately f»erambulated the leaves in search of a place suited to her purpose, and passing under a leaf began to lay, deposit- ing six eggs within a quarter of an hour. Each time she placed herself as if she wished to cut into the leaf with her saw ; but, upon taking out the leaf, the eggs appeared rather projecting than lodged in its substance. They adhered so firmly, however, that they could not be de- tached without crushing them. He could not discover * Hints on Orchards, p. 57. f See chap. vii. for a description of this curious instrument. CATERriLLAHS. 175 a a a, Saw-fly of the goosel:erry (Nematus Rtbtsii, Stephens), b, its eggs on the nervures of a leaf, d d, the caterpillars eating, c, one rolled lip. /", one extended. any groove ;* but we think it likely that a minute cut is made in the exterior membrane of the leaf, the edges of which grasp and hold firm the part of the egg which is thrust into it by the insect. Be this as it may, the cater- pillars are hatched in two or three weeks ; and they feed in company till after midsummer, frequently stripping both the leaves and fruit of an extensive plantation. The caterpillar has six legs and sixteen prolegs, and is of a green colour mixed with yellow, and covered with minute black dots raised like shagreen. In its last skin it loses the black dots and becomes smooth and yellowish white. The Caledonian Horticultural Society have published a number of plans for destroying these cater- pillars. An allied species of saw-fly (Nematus Caprece, * Reaumur, v. 125. 176 RAVAGES OP INSECTS. ; Stephens) frequently becomes extensively destructive to several species of willow, sallow, and osier. It is so like that of the gooseberry and that of the willow (Ne- matus salicis), which is not British, that it has been con- founded with these by Fabricius, Stewart, Gmelin, and other authors. In the summer of 1828, we observed a considerable group of young standards of the golden osier (Salix vitellhia), in a nursery at Lewisham, rendered quite leafless by these caterpillars ; which, when feeding, throw themselves into singular postures by holding only with their fore feet. The fly appears in spring, and places its eggs in a round patch on the back of the leaf, and not along the ner\ ures, like the gooseberry saw-fly. During the three last summers, we also remarked that the alders (Abius glutinosa) along the banks of the Ravensbourne, in Kent, were extensively stripped of their leaves by a saw-fly caterpillar, very like the pre- ceding, but of a larger size. (J.U.) It appears to be the same as one figured by Reaumur* (Selandria Alni? Stephens). Another slimy caterpillar of a saw-fly, allied to that of the cherry {Tenthredo CerasiJ, is called the slug-worm in North America, where it has increased so numerously as to threaten the entire destruction of fruit-trees, in- cluding the cherry, plum, pear, and quince. Where they are numerous, the air becomes loaded with a dis- agreeable and sickly effluvium. The history of this orchard pest has been admirably written by Professor Peck.f When a turnip crop has been fortunate enough to escape the ravages committed on it in the seed leaf by a small jumping beetle (Haltica nemonon, Illiger), and by a root weevil (Nedyus contractus, Stephens), a no less formidable depredator sometimes appears in a cater- pillar belonging to the saw-fly family (Tenthredinidce), and apparently of the genus AtJialia. An instance is recorded by Marshall, in the Philosophical Transactions, * Reaumur, vol. v., pi. 11, fig. 1, 2. f Nat. Hist, of the Slug- Worm, Boston, 1799. CATERPILLARS. 177 , Neiuatus caprco", on the osier ; b, Selandria alni? on the alder. of many thousand acres having had to be ploughed up on account of the devastations caused by these insects. It is, he informs us, the general opinion in Norfolk that they come from over-sea ; and a farmer averred that he saw them arrive in clouds so as to darken the air, while the fishermen reported that they had repeatedly wit- nessed flights of them pass over their heads when they were at a distance from land. On the beach and the cliffs, indeed, they lay in heaps, so that they might have been taken up with shovels ; while three miles inland they crowded together like a swarm of bees.* '■'■ Phil. Trans, vol. Ixxiii. p. 317- VOL. ir. I 178 RAVAGES OF INSECTS. We have little doubt, however, that these details are put in an inverse order ; as frequently occurs in histories of the proceedings of insects by those but little acquainted with their habits. Insects of this family, indeed, seldom fly far, and could not at all events cross the sea, unless it might be a narrow bay or inlet ; and if they had, we ought to have heard of their departure as well as their arrival, since their extraordinary number could not have failed to attract public notice on other shores. The na- ture of these insects is to lie in the pupa state during the winter under ground ; and when, at its appointed time, the fly comes forth, it only lives to lay its eggs, usually dying within a few days or weeks. It must have been, therefore, after the laying their eggs on the turnips, and not before, that clouds of the flies were seen at sea and on the shore, though not arriving, but going away. They were, doubtless, impelled by that restless desire of change felt by all animals when death is approaching, and v^hich in tropical countries is yearly exemplified in the destruction of locusts, for these always make for the sea, and perish there. But though they were thus got rid of in August, 1782, they left a progeny behind them in the black caterpillars which were hatched from their eggs. In the summer of 1783, accordingly, we are told by Mr. Marshall, that whole districts were ravaged by them, — the descendants, of course, in the second gene- ration, of the saw-flies which perished on the beach and at sea the preceding autumn. Some caterpillars, which either conceal themselves under ground, or feed on roots and the wood of trees, do considerable injury, without apparent cause ; and often give occasion to the popular notions respecting mysterious blights. In this manner will the caterpillars of the ghost moth (Hepialus Humuli) gnaw the roots of the burdock, and, what is of more consequence, of the hop plant, till the shoots are weakened, and the leaves droop in bright sunshine. We have repeatedly seen, in the gardens about Lee, a large branch of the red-currant bush, though previously healthy and loaded with fruit, all of a sudden droop and wither, giving good cause to CATERPILLARS. 179 surmise, except in the leaves not being brown or parched, that it had been struck with lightning. On cutting into such branches, however, the cause was uniformly found to be the ravages of the caterpillar of the currant hawk- moth {jEgeria tipuliformis, Stephens), which abounds in the vicinity. But we have also remarked that it only occasionally produces this effect upon the trees ; for several bushes upon which we have found old pupa-cases projecting from the bark, remained healthy and unin- jured. (J.R.) Sir Joseph Banks showed Mr. Kirby a cur- rant branch perforated by this caterpillar to the pith, and said the size of the fruit was in consequence diminished.* In Germany it is reported to destroy even large bushes of , the red currant. There can be no doubt that the caterpillars of the goat-moth frequently destroy willow, poplar, and oak trees, of considerable magnitude ; but the mother moth seems to prefer laying her eggs upon those which have already begun to decay. A black poplar tree, not thicker than a man's leg, and stripped on one side of more than a foot of the bark, was bored by above a dozen caterpillars of the clear underwing (jEgeria asiliformis, Stephens), without seeming to have its growth at all retarded.! It does not appear that a minute moth, called by Leeuwenhoeck, who writes its history, the wolf, and by Haworth the mottled-woollen (Ph. lYnea granella, LiNN^us), is so abundant in Britain as to do much da- mage to the grain stored in granaries, upon which it feeds. But it seems to have created considerable alarm on the Continent. It has been found near London, and ?nai/ increase with us. The caterpillar, Vvhich is smooth and white, ties together with silk several grains of wheat, barley, rye, or oats, weaving a gallery between them., from which it projects its head while feeding ; the grains, as Reaumur remarks, being jiH'evented from rolling or slipping by the silk which unites them. He justly ridi- cules the absurd notion of its filing off the outer skin of * Kirby and Sptnce, vol. i. p. 197. f See vol. i. p. ISl. I 2 180 RAVAGES OF INSECTS. the wheat by riibbirij^ upon it with its body, the latter being the softer of the two ; and he disproved, by ex- periment, Leeuwenhoeck's assertion that it will also feed on woollen cloth. It is from the end of May till the beginning of July that the moths, which are of a silvery grey, spotted with brown, appear and lay their eggs in granaries. The caterpillar of another still more singular grain moth (Tinea Hordei^ Kirby and Spence) proves some- times very destructive to granaries. The mother moth, in May or June, lays about tvventy or more eggs on a grain of barley or wheat ; and when the caterpillars are hatched they disperse, each selecting a single grain. M. Reaumur imagines that sanguinary wars must some- times arise, in cases of preoccupancy, a single grain of barley being a rich heritage for one of these tiny insects ; but he confesses he never saw such contests. When the caterpillar has eaten its way into the interior of the grain, it feeds on the farina, taking care not to gnaw the skin nor even to throw out its excrements, so that except the little hole, scarcely discernible, the grain appears quite d ^^- ) #^ Transformations of the grain moths, a, grain of barley, including a caterpillar ; b, c, the grain cut across, seen to be hollowed out, and divided by a partition of silk; d, the moth (Tinea Horrid); e, grains of wheat tied together by the caterpillar, /; g, the moth (Euplocamus granella). CATERPILLARS. 181 sound. When it has eaten all the favina, it spins itself a case of silk within the now hollow grain, and changes to a pupa in November,* Two other caterpillars of a different family, the honey- comb moth (Galleria cercana, Fabr,), and the honey moth (G. olvearia, Fabr.), the first having square, and the second rounded wings, f do very considerable da- mage to the hives of bees. The moths of both, accord- ing to Reaumur, appear about the end of June or be- ginning of July ; and when in danger they run rather than fly, gliding with such celerity that they can easily elude the vigilance of the bees, which, indeed, if we may trust Swammerdam, never attack them, nor prevent their entrance into the hives, unless they chance to brush against them in their passage. But Reaumur actually saw the bees pursue one, though without success. It becomes easy for a moth, at all events, to lay eggs among the combs ; or, as Keys says, at the entrance of the hive ; this writer adds, *' she spins a close and strong web to defend the young;" J which is impossible, as no insect, subsequent to its larva state, can spin. The caterpillar of the first species, " wherever it passes," says Swammerdam, " gnaws round holes through the waxen cells, one caterpillar sometimes breaking open and destroying fifty or sixty cells. Wherever it pene- trates it always fabricates a hollow tubulated web, in which, as a rabbit in its burrow, it can very swiftly pass from one part to another, and speedily run back again. It fills the whole comb with such webs, and turns itself in them every way into various bendings and windings ; so that the bees are not only perplexed and disturbed in their work, but they frequently entangle themselves by the claws and hairs of their legs in those webs, and the w^hole hive is destroyed." The other species he accuses of being not only de- structive to the wax, but to the bees themselves. " I * Reaumur, Mem., vol. ii. p. 4S6, &c. f Stephens's Catalogue, vol. ii. p. 213. I KeySj Treatise on Bees, p. 173, edit. 1814. 182 RAVAGES OF INSECT3. Transformations of the lioneycomb moths, 'a a a, Galleries of the cell-borinj,' caterpillar ; 6, the female ; c, the male moth (6V///cj'rt nlve- aria) ; dd dd, jjalleries of the wax eating caterpillar, e, seen at the en- trance ; /, the same exposed ; g, its cocoon ; h, the moth {Galleria cereana). saw one of these little caterpillars," he says, " whilst it was still small, and was breaking the cells in which the pupa of the bees lie, and eating the wax there, cover up these, pupge with its excrements, so that they could scarcely be known." He adds with great naivete, " I have learned these matters much against my inclination, and have been full of wrath against the insect for thus defiling and killing some bee pupae which I had designed to observe in their changes."* M. Bazin, a friend of Reaumur's, discovered the cater- pillar of a moth of this order feeding on chocolate, of which it seemed very choice, always preferring that * Swammerdam, vol. i. p. 225. GRuns. 188 which had the finest flavour. The moth is sometimes produced in September, and sometimes in the beginning of the following- summer. It is probable that, like the cheese-fly, it might, in default of chocolate, select some other aliment.* Grubs. We frequently hear farmers and gardeners complaining that their produce is destroyed by '"'■the grub;" they might with equal propriety accuse "Me bird" when their ripe seeds are devoured by sparrows, chaffinches, linnets, and other seed-eaters. Instead of one sort of grub, as the expression seems to indicate, we are far under the mark in reckoning a thousand species indige- nous to Britain, each peculiar in its food and its manners. We shall, however, adhere as nearly as possible to the terms in common use ; but as the larvas of the crane-flies {TipulidcB^ Leach), being without legs, cannot be accu- rately ranked with the legged grubs of beetles, we shall consider them as maggots, though they are usually termed grubs by the farmers. The most destructive, perhaps, of the creatures usually called grubs, are the larvae of the may-bug or cockchafer (JMelolontlia vulgaris), but too well known, particularly in the southern and midland districts of England, as well as in Ireland, where the grub is called the Connaught worm ;1' but fortunately not abundant in the north. We only once met with the cockchafer in Scotland, at Som, in Ayrshire. (J. R.) Even in the perfect state, this insect is not a little destructive to the leaves 6f both forest and fruit trees. In 1823, we remember to have observed almost all the trees al^oat Dulwich and Cam- berwell defoliated by them ; and Salisbury says, the leaves of the oaks in Richmond Park were so eaten by them, that scarcely an entire leaf was left. But it is in their previous larva state that they are most destructive, as we shall see by tracing their history. * Reaumur, vol. iii. p. 277. f Bingley, Aiiim. Biog. vol. iii. p. 230. 1 84 EAVAGES OF INSECTS. The mother cockchafer, when about to lay her eggs, digs into the earth of a meadow or corn-field to the depth of a span, and deposits them in a cluster at the bottom of the excavation. Roscl, in order to watch their proceed- ings, put some females into glasses half-filled with earth, covered with a tuft of grass and a piece of thin muslin. In a fortnight, he found some hundreds of eggs depo- sited, of an oval shape and a pale yellow colour. Placing the glass in a cellar, the eggs were hatched towards autumn, and the grubs increased remarkably in size. In the following IMay they fed so voraciously that they re- quired a fresh turf every second day ; and even this proving too scanty provender, he sowed in several gar- den pots a crop of peas, lentils, and salad, and when the plants came up he put a pair of grubs in each pot ; and in this manner he fed them through the second and third years. During this period, they cast their skins three or four times, going for this purpose deeper into the earth, and burrowing out a hole where they might effect their change undisturbed ; and they do the same in winter, during which they become torpid and do not eat. When the grub changes into a pupa, in the third autumn after it is hatched, it digs a similar burrow about a yard deep ; and when kept in a pot, and prevented from going deep enough, it shows great uneasiness and often dies. The perfect beetle comes forth from the pupa in January or February ; but it is then as soft as it was whilst still a grub, and does not acquire its hardness and colour for ten or twelve days, nor does it venture above ground before May, on the fourth year from the time of its hatching. At this time, the beetles may be observed issuing from their holes in the evening, and dashing themselves about in the air as if blind. During the three summers then of their existence in the grub state, these insects do immense injury, burrowing between the turf and the soil, and devouring the roots of grass and other plants ; so that the turf may easily be rolled off*, as if cut by a turfing spade, while the soil underneath for an inch or more is turned into soft mould GRUBS. 185 Transformations of the cockchafer {Mcklmthn rulgarh). a. Newly hatched larvae, b, larva, one year old. c, the same larva at the second year of its growth, d, the same three years old. e, section of a bank of earth, containing the chrysalis of the fourth year, /', the cliafer first emerging from the earth, g, the perfect chafer in a sitting posture, /i, the same Hying. like the bed of a garden. Mr. Anderson, of Norwich, mentions having seen a whole field of fine flourishing grass so undermined by these grubs, that in a few weeks it became as dry, brittle, and withered as hay.* Binglej also tells us that "about sixty years ago, a farm near * Fhilosoph. Trans, xliv. 579. I 3 186 RAVAGES OF INSECTS. Norwich was so infested with cockchafers, that the farmer and his servants affirmed they gathered eighty bushels of them ; and the grubs had done so much injury, that the court of the city, in compassion to the poor fellow's mis- fortune, allowed him twenty-five pounds." * In the year 1785, a farmer, near Blois, in France, employed a num- ber of children and poor persons to destroy the cock- chafers at the rate of two liards a hundred, and in a few days they collected fourteen thousand. f " I remember," says Salisbury, " seeing, in a nursery near Bagshot, several acres of young forest trees, parti- cularly larch, the roots of which were completely de- stroyed by it, so much so that not a single tree was left alive." J We are doubtful, however, whether this was the grub of the cockchafer, and think it more likely to have been that of the green rose-beetle {Cetonia aurata)^ which feeds on the roots of trees. The grub of an allied genus, the midsummer chafer (^Zantheiimia solstitialis^ Leach), has for the last two years been abundant on Lewisham Hill, Blackhoath, doing considerable injury to herbage and garden plants. This beetle may be known fi-om being smaller and paler than the cockchafer, and from its not appearing before midsummer. The grub is very similar. The best way of preventing the ravages of these in- sects would be to employ children to collect the perfect insects when they first appear, before they lay their eggs ; but when a field is once overrun with the larva, nothing can be done with it, except paring and burning the surface, or ploughing it up, and turning in a flock of ducks or other poultry, or a drove of pigs, wdiich are said to eat these grubs, and to fatten on the fare. Drenching the field with stable urine§ by means of reservoir-carts, like those used for watering roads, would, it sufficiently done, both kill the grubs and beneficially manure the land. * Anim. Biog. iii. 233. f Anderson's Recr. in Agricult. iii. 420. j Hints, 71. § See the Harleian Dairy System, p. 222. GRUBS. 187 The grub called the wire-ivorm, though not very appro- priately, is the larva of one of the spring or click beetles (Hemirhipiis lineatus, and II. obscurr/s, Latreille), known by their long flattish body, and their power of springing with a clicking sound out of the hand when caught. In some works on agriculture, the larva of a com- mon crane-fly (Tipnla oleracea or T. crocata) is called the u'ire-ivonn, — we suppose by mistake.* The grubs of the click-beetles, just alluded to, are said by Bierscanderf and by Mr. Paul of Starston, Norfolk, ;}: who watched their transformations, to continue five years before pro- ducing the perfect insect. During this time the grub feeds chiefly on the roots of wheat, rye, oats, barley, and grass ; but seems also sometimes to attack the larger roots of potatoes, carrots, and salads. Its ravages are often so extensive as to cut off" entire crops of grain. It appears to be most partial to land newly broken up ; and has not been found so abundant in meadows and pastures, unless in fields recently laid down with grass. "The wire- worm," says Spence, " is particularly destructive for a few years in gardens recently converted from pasture ground. In the botanic garden at Hull, thus circum- stanced, a great proportion of the annuals sown in 1813 were destroyed by it. A very simple and effectual re- medy, in such cases, was mentioned to me by Sir Joseph Banks. He recommended that slices of potatoes, stuck upon skewers, should be buried near the seeds sown, examined every day, and the wire-worms, which collect upon them in great numbers, destroyed." § The wire-worm is long, slender, and very tough and hard ; but otherwise it has no resemblance to wire, being whitish in colour, of a flattish form, and jointed or ringed. Its breathing spiracles, two in number, are on the back of its last ring. An insect of this family (Elater nociilucus, Lixn.) is exceedingly destructive, in the West Indies, to the sugar- * See Loudon's Eiicycl. of Agricult. 6. 6921. f Act. Holm. 1779, p. 284. + Kirbv and Spence, i. 182. ^^ lutr. i. 1S2-3. ' 188 RAVAGES OF INSECTS. «j Wire worm ; I, Click beetle. cane ; the grub, according: to Humboldt and Bonpland, feeding on its roots and killing the plants." * Instances are by no means rare, however, of insects being accused of depredations of which they are not guilty, from the mere circumstance of their being found in abundance where ravages have been committed by others that have naturally disappeared. It is not im- probable that this was the case with a grub of some beetle (Staphylinidci^ ?) mentioned by Mr, Walford, and mistaken by him for the wire-worm. Out of fifty acres of wheat sown in 1802, ten had been destroyed in Octo- ber by this grub eating into the centre of the young stem an inch below the surface and killing the plant. f It seems still more probable that the grub of a native beetle (Zabrvs gibhus, Stephe.ns), which has been found in considerable numbers near Worthing, Brighton, Hastings, aid Cambridge, has been unjustly blamed as a destroyer ot" corn ; though we have the respectable authority of Germar, who, with other members of the society of Natural History of Halle, imagined he had ascertained the fact. In the spring of 1S13, about two hundred and thirty acres of young wheat are said to have been destroyed by it ; and it is farther supposed to be * Geog. des Plaiites, 136. ■j- Linn. Trans, ix. 156-61. GRUBS. 189 the same insect which caused great destruction in Italy in 1776. This grub is said to take probably three years in coming to a beetle, in Avhich state it is alleged to clamber up the stems at night to get at the corn. It is important to remark, that along with these grubs wore found those of a chafer {Melolontha rnficornis^ Fabr,), in the pro- portion of about a fourth.* a b a, Zabrus gibbus ; h, Melolontha ruficornis. To this account Mr. Stephens appends the shrewd questions — " May not these herbivorous larvte [of the chafer] have been the principal cause of niiscliief to the wheat, while those of the Zabrus rather contributed to lessen their numbers than to destroy the corn ? And is it not probable that the perfect insects ascend the corn for the purpose of devouring the insect parasites thereon ? This is a subject," he justly adds, " that requires inves- tigation, as it is highly important, for the interests of the agriculturists in those districts where the insect abounds, that the question should be thoroughly set at rest ; be- cause, should the Zabri depart from the habits of the group to which they belong, and become herbivorous instead of carnivorous, their destruction would be de- sirable ; while, on the contrary, if they destroy the de- vourers of our produce their preservation should be attempted." f * Germar, Mag. der Entomol., i. 1-10; and Kirby and Spence, i. 1G9. t Stephens, Illustrations, i. Mandib. pp. 4 and 110. 190 KAVAGES OF INSECTS. Wc have little doubt that Mr. Stephens is right, and Gerniar wrong ; but it would be improper to decide the question by analogy unsupported by direct exjieriment. One thing is certain, that both this family (Harpalidce^ MacLeay) and the whole section (Adephaga, Clair- ville) are not herbivorous, but carnivorous.* Similar errors will come under our notice, as we proceed, not more defensible than that of the old soldier causing cater- pillars in France. Even when agricultural produce escapes being de- voured at the root, or the young shoots eaten up, the seeds are often made the prey of the grubs of beetles and weevils. Among the first, the gnawing beetles (Bru- chidcs. Leach) are very destructive. In North Ame- rica, the pea-beetle (SrucJms Pisi\ Linn.) commits such extensive depredations on pulse, that in some districts the sowing of peas has been abandoned as useless. Ivalm, the Swedish traveller, having witnessed these depreda- tions in America, became quite alarmed when he disco- vered the insect among some peas he had brought to Sweden, lest he should be the means of introducing so formidable a pest.f His fears seem to us to have been in a great measure groundless ; for, probably, the insect may be indigenous to Sweden, as it is to Britain, though from circumstances of climate, and other causes, it is seldom produced in such numbers with us as to occasion extensive damage. It may have been the same or an allied species of grub mentioned by Amoroux as having spread an alarm in France in 1780, when the old fancy of its being poisonous induced the public authorities to prohibit peas from being sold in the markets. J The in- sect most destructive to our peas is the pulse-beetle (^Bruclms grcmarms, Li^is'.), v.hich sometimes lays an egg on every pea in a pod, which the grub, when hatched, destroj's. In the same way, clover-seed is * See an illustration in vol. i. p. 196. f Kalm's Travels, vol. i. p. 173. X Amoroux, Insectes Venimeux^ 2SS. Kirby and Spence, i. 177. GRUBS. 191 often attacked hy two or more species of small weevil (Apwn, Hekbst), known by the yellow colour of their thighs or their feet ; and when the farmer expects to reap considerable profit, he finds nothing but empty husks. We ha\e mentioned the ravages committed in grana- ries by the caterpillars of small moths ; but these are rivalled in the work of destruction by several species of grubs. One of these grubs is called by the French ca- delle {Trogosita mauritanica, Olivier), and is reported to have done more damage to housed grain than any other insect.* The pest of the granaries, which is but too well known in this country, is the grain weevil (Ca- landra granaria, Clairville), the same, probably, which is mentioned by Virgil, Populatque ingentem fariis acervum Curculio. Gsoi-g. i. 87. The high stacks of corn Are wasted by the weevil. Trapp. Kirby and Spence calculate that a single pair of wee- vils may produce in one season 6000 descendants ; and they were told by an extensive brewer that he had col- lected and destroyed them by bushels, f — meaning, no doubt, insects and damaged grain together. Another beetle grub, popularly called the meal-worm, the larva of Tenebrio molitor, Li>'>:., which lives in that Corn weevil {Calanira granaria), magnified. * Olivier, ii. 19. fln'r. M73. 192 BAVAGES OF INSECTS. state two years, does no little damage to flour, as well a? to bread, cakes, biscuit, and similar articles. Accounts arc also given of the ravages committed by the grubs of other beetles, of several species apparently not well as- certained, upon ditFerent sorts of provisions, such as bacon, ham, dried tongues, ship-biscuit, &c. Sparrman tells us that he has witnessed the ground peas on ship- board so infested with these grubs, that they were seen in every spoonful of the soup. In the case of soup, or of other food which has been exposed to heat, the only inconvenience is the disgust which must ensue ; but, un- fortunately, there may sometimes occur circumstances of s, more serious nature, — from either the eggs or the in- sects themselves being incautiously swallowed alive. We do not wish, however, to create, so much as to allay, the fears entertained by those who are unacquainted with the habits of insects ; and nothing we are persuaded will do this more effectually than a statement of facts well ascertained. " Several people,'' says the Abbe de la Plucbe, " never eat fruit because they believe that spiders and other insects scatter their eggs upon it at random ;"* but even if this M-ere so, as it is not, it would be impos- sible for the young, should they be hatched in the sto- mach, to live there for an instant. The possible cases in which this may occur we shall now briefly notice ; they are fortunately very rare. The grub of the nut weevil (Bakminus Nucum, Ger- mar) might, perhaps, by rare accident, get into the stomach, either of man or of the quadrupeds which feed on nuts ; but as it is by no means so tenacious of life as the grub of the churchyard-beetle {Blaps 7nor- tisaga) it is unlikely that it would produce any con- siderable disorder. The wee\41 in question, like the rest of its congeners, is furnished v/ith an instrument for depositing its eggs considerably difterent from those of the ichneumons and saw-flies. For this purpose the weevil makes use of its long horny beak (^Rostrurn) to * Spectacle de la Nature, i. Q5, GRUDS OF BEETLES. 193 drill a hole in filberts and hazel-nuts, uliilc in their young and soft state, about the beginning of August. The mother weevil may then be seen eagerly running over the bushes, and it would appear that she always rejects the nuts in which one of her neighbours may have previously laid an egg ; at least we never find two grubs in the same nut. The egg which is thus thrust into the young nut, is of a brown colour, and is hatched in about a fortnight, the grub feeding on the interior of the shell as well as the soft pulp, till the one becomes too hard and the other too dry to be nutritive. It is remarkable that, during this period, he takes care not to injure the kernel, but permits it to ripen before he attacks it. Had he done this prematurely, he would have ultimately been starved, as he has not the power of perforating another nut when the first is consumed. It is said also that he is very careful to preserve the original hole made by the mother, by gnawing around its inner edges, in order to facilitate his exit,* which he efiects when the nut falls to the ground in September or October. The hole found in the nut appears much too small to have admitted of its passage ; but from being very soft it no doubt stretches itself out for the purpose, using its short claws as instruments of motion. Iloscl, in order to observe the transformation of these nut grubs, put a number of them, at the commencement of winter, into glasses half filled with earth, coveied with green turf. All of them dug directly down into the earth, remained there all the winter, and did not change into pupae till the following June ; the perfect weevils appeared from the 1st till about the 20th of August, but still kept under ground for the first week after their change. "During the autumn," says Salisbury, "we fi'C- quently observe a small red weevil busily employed in tra- versing the branches of a])ple-trees, on which it lays its eggs by perforating the bloom buds. In the sj>ring these hatch, and the grubs feed on the petals of the * Bingley, Animal Biography, vol. iii., p. 251. 194 RAVAGES OF INSECTS. Nut and apple-tree beetles. A, a branch of the filbert -tree, a, egg hole in the nut; 6, exit hole of the grub B, the larva of the nut beetle. C, the same in the pupa state. D, female beetle. E, male beetle, c, the beetle that destroys the bloom- hud of the apple-tree; a, the same in the larva state ; b, the chrysalis of the same. flowers, drawing up the whole flower into a cluster by- means of their web. The bloom thus becomes de- stroyed, and the grub falls to the ground, where it lays itself up in the chrysalide state ; and in the autumn afterwards we tind the weevil renewed, which again per- forates the buds, and causes a similar destruction in the following spring. Mr. Knight, in his treatise on the apple, mentions a beetle which commits great destruction on the apple-trees in Herefordshire ; but I do not think it the same as the one I have described above, and which is very common in the gardens near London."* Salis- bury's weevil is probably the Anthonomiis Pomorum of Germar ; and Knight's, his Pohjdrusus Mali. Another weevil (JRhynchites Bacchus, Herbst), one of our most splendid but not very common native insects, bores into the stone of the cherry, &c., while it is young and soft, and deposits an e^^ there, as the nut weevil does in the nut. * Salisbury's Hints on Orchards, p. 92. GKUUS or BEETLES. 195 Perhaps the most voracious grub on record is that of a large and beautiful beetle (Calosoma sycophanta^ We- ber), which is rare in Britain. It is sometimes found in the nests of the processionary and other gregarious caterpillars, so gorged with those it has devoured that it can scarcely move without bursting. xSot contented Mith this prey alone, however, the younger grubs are said '* often to take advantage of the helpless inactivity into which the gluttony of their maturer comrades has thrown them, and from mere wantonness, it should seem, when in no need of other food, pierce and devour them."* It is a familiar occurrence to those v,ho breed insects to find caterpillars, whose natural food is leaves, devouring others in the same nurse-box ; and without any apparent discrimination whether these are the pi-ogeny of their own mother, or of a different species. f (J.R.) We have frequently observed a very remarkable in- stinct in the grubs of a species of beetle {Scolytns de- structor, Geoitroy), which lives under the dead bark of trees. The mother insect, as is usual with beetles, deposits her eggs in a patch or cluster in a chink or hole in the bark ; and when the brood is hatched, they begin feeding on the bark which had formed their cradle. There is, of course, nothing wonderful in their eating the food selected by their mother ; but it appears that, like the caterpillars of the clothes moth, and the tent insects, they cannot feed except under cover. They dig, there- fore, long tubular galleries between the bark and the wood ; and, in order not to interfere with the riins of their brethren, they branch off from the place of hatch- ing like rays from the centre of a circle : though these are not always in a right line, yet, however near they may approach to the contiguous ones, none of them ever break into each other's premises. We cannot but ad- mire the remarkable instinct implanted in these grubs by their Creator ; which guides them thus in lines di- verging farther and farther as they increase in size, so * Kirby and Spence, vol. i. p. 277. t See also De Geer, i. 5o3, &c., and Reaumur, ii. 413. 196 RAVAGES OF INSECTS. Bark mined in ravs bv beetle-L'rubs. that they are prevented from interfering with the com- forts of one another. The various instances of voracity which we have thus described sink into insignificance when compared with the terrible devastation produced by the larvae of the locust {Locusta migratoria, Leach), — the scourge of Oriental countries, "A fire devoureth before' them," says the Prophet Joel, " and behind them a flame burn- eth : the land is as the garden of Eden before them, and behind them a desolate wilderness ; yea, and nothing shall escape them. The sound of their wings is as the sound of chariots, of many horses running to battle ; on the tojis of mojjntains shall they leap, like the noise of a flame of fire that devoureth the stubble, as a strong people set in battle array. Before their faces, the people shall be much pained, all faces shall gather blackness. They shall run like mighty men ; they shall climb the wall like men of war ; and they shall march every one in his ways, and they shall not break their ranks ; neither shall one thrust another."* * Joel ii. 2, &c. JLOCUSTS. 197 The intelligent traveller, Dr. Shaw, was an eye-wit- ness of their devastations in Barhary in 1724, where they first appeared about the end of March, their num- bers increasing so much in the beginning of April as literally to darken the sun ; but by the middle of INIay they began to disappear, retiring into the jNIettijiah and other adjacent jdains to deposit their eggs. "These were no sooner hatched in June," he continues, "than each of the broods collected itself into a compact body, of a furlong or more in square ; and marching afterwards directly forwards toward the sea, they let nothing escape them, — they kept their ranks like men of war ; climbing over, as they advanced, every tree or wall that was in their way ; nay, they entered into our very houses and bed-chambers, like so many thieves. The inhabitants, to stop their progress, formed trenches all over their fields and gardens, which they filled with water. Some placed large quantities of heath, stubble, and other combustible matter, in rows, and set them on fire on the approach of the locusts ; but this was all to no purpose, for the trenches were quickly filled up, and the fires put out, by immense swarms that succeeded each other. " A day or two after one of these hordes was in mo- tion, others were already hatched to march and glean after them. Having lived near a month in this manner, they arrived at their full growth, and threw off their nympha state by casting their outward skin. To pre- pare themselves for this change, they clung by their hinder feet to some bush, twig, or corner of a stone ; and immediately, by using an undulating motion, their heads would first break out, and then the rest of their bodies. The whole transformation was performed in seven or eight minutes ; after which they lay for a small time in a torpid, and, seeminglj^, in a languishing condition ; but as soon as the sun and the air had hardened their wings by drying up the moisture that remained upon them after casting their sloughs, they resumed their former voracity, with an addition of strength and agility. Yet they con- tinued not long in this state before they were entirely dispersed." * * Shaw's Travels, p. 2S7. 198 RAVAGES OF INSECTS. It is difficult to form an adequate conception of the swarms of locusts which, in 1797, invaded the interior of southern Africa, as recorded by Mr. Barrow. In the part of the country where he was, the whole surfiice of the ground, for an area of nearly two thousand square miles, might .literally be said to be covered with them. The water of a very wide river was scarcely visible, on account of the dead carcases of locusts that floated on the surface, drowned in the attempt to come at the reeds that grew in it. They had devoured every blade of grass, and every green herb, except the reeds. But they are not precisely without a choice in their food. When they attack a field of corn just come into ear, they first, according to Mr. Barrow, mount to the summit and pick out every grain before they touch the leaves and stem, keeping the while constantly in motion, with the same intent of destruction always in view. When the larvag, which are much more voracious than the perfect insects, are on a march during the day, it is utterly impossible to turn the direction of the troop, and this seems usually to correspond with that of the wind. Towards the setting of the sun the march is discontinued, when the troop di- vides into companies that surround the small shrubs, or tufts of grass, or ant-hills, in such thick patches, that they appear like so many swarms of bees ; and in this manner they rest till day-light. At these times it is that the farmers have any chance of destroying them ; this they sometimes effect by driving among them a flock of two or three thousand sheep, by whose restlessness great numbers of them are trampled to death. The year 1797 was the third of their continuance in Sneuwberg ; and their increase had been more than a million-fold from year to year. This district, however, had been entirely free from them for ten years preceding their visit in 1794. Their former exit was singular : all the full-grown insects were driven into the sea by a tempestuous north-west wind, and were afterwards cast up on the beach, where thej formed a bank of three or four feet high, and extending to a distance of nearly fifty miles. When this mass be- came putrid, and the wind was at south-east, the stench LOCUSTS. ' 199 was sensibly felt in several parts of Sneuwberg, although distant at least a hundred and fifty miles.* Pallas gives a more detailed account of the daily pro- ceedings of the larvae of the Italian locust {Locusta Italica, Leach). " In serene weather," he tells us, " the locusts are in full motion in the morning, imme- diately after the evaporation of the dew ; and if no dew has fallen, they appear as soon as the sun imparts his genial warmth. At first, some are seen running about like messengers among the reposing swarms, which are lying partly compressed ujjon the ground at the side of small eminences, and partly attached to tall plants and shrubs. Shortly after the whole body begins to move forward in one direction, and v.ith little deviation. They resemble a swarm of ants, all taking the same course, at small distances, but without touching each other: they uniformly travel towards a certain region as fast as a fly can run, and without leaping, unless pursued ; in which case, indeed, they disperse, but soon collect again and follow their former route. In this manner they advance from morning to evening without halting, frequently at the rate of a hundred fathoms and upv.ards in the course of a day. Although they prefer marching along high roads, foot-paths, or open tracts, yet, when their progress is opposed by bushes, hedges, and ditches, they penetrate through them : their way can only be im- peded by the waters of brooks or canals, as they are apparently terrified at every kind of moisture. Often, however, they endeavour to gain the opposite bank, with the aid of overhanging boughs ; and, if the stalks of plants or shrubs be laid across the water, they pass in close columns over these temporary bridges, on which they even seem to rest, and enjoy the refreshing coolness. Towards sun-set, the whole swarm gradually collect in parties, and creep up the plants, or encamp on slight eminences. On cold, cloudy, or rainy days, they do not travel. As soon as they acquire wings, they progres- sively disperse, but still fly about in lai*ge sv,arms."f * Barrow's Travels in South Africa, p. 257. f Travels in Russia, ii. 422-6. 200 RAVAGES or INSECTS. "When Captains Irby and Mangles were travelling round the southern extremity of the Dead Sea, in the end of May, they had an opportunity of observing these insect depredators. " In the morning," say they, " we quitted Shobek. On our way we passed a swarm of locusts that were resting themselves in a gully ; they were in sutficicnt numbers to alter apparently the colour of the rock on which they had alighted, and to make a sort of crackling noise while eating, which we heard be- fore we reached them. Volney compares it to the fo- raging of an army. Our conductors told us they were on their way to Gaza, and that they pass almost annually."* Even our own island has been alarmed by the appear- ance of locusts, a considerable number having visited us in 1748 ; but they happily perished without propagating. Other parts of Europe have not been so fortunate. In 1650 a cloud of locusts were seen to enter Russia in three different places ; and they afterwards spread themselves over Poland and Lithuania in such astonishing multitudes, that the air was darkened, and the earth covered with their numbers. In some places they were seen lying- dead, heaped upon each other to the depth of four feet ; in others they covered the surface of the ground like a black cloth : the trees bent with their weight, and the Locust. * Irby and Mangles' Travels in Egypt and Syriaj p. 113. MAGGOTS. 201 ihimage the country sustained exceeded computation.* They iiave frequently come also from Africa into Italy and Spain. In the year 591 an infinite army of locusts, of a size unusually large, ravaged a considerable part of Italy, and being at last cast into the sea (as seems for the most part to be their fate), a pestilence, it is alleged, arose from their stench, which carried off nearly a mil- lion of men and beasts. In the Venetian territory, like- wise, in 1478, more than 30,000 persons are said to have perished in a famine chiefly occasioned by the depre- dations of locusts. t Maggots. Adhering to the distinction of terming those larva? which are destitute of feet, maggots, we shall notice here a very destructive one, which is sometimes popularl}" cjdled the grub, and sometimes confounded with the wire- worm. |l* We allude to the larvae of one or two common species of crane-flies {Tipulidce) , well known by the provincial names of father-long-legs, Jenny-spinne:-s, and tailors. These insects are so common in some mea- dows, that, being very shy and fearful of danger, they rise in swarms at every step — some of them flying high, others only skipping over the grass, and others running and using their long legs as the inhabitants of marshy countries use stilts, and employing their wings like the ostrich to aid their limbs. These flies deposit their eggs in the earth ; sometimes in grass-fields or moist meadows, and sometimes in the tilled ground of gardens and farms. For this purpose the female is provided with an ovipositor well adapted to the operation, consisting of a sort of pincers or Ibrceps of a horny consistence, and sharp at the point. By pres- sure, as Reaumur says, the eggs may be extruded from this in the same way as the stone can be easily squeezed out of a ripe cherry, as in the following figure. * Biugley, Anim. Biog. iii. 2S0. t Mouffet, Theatr. Insect. 123. X See Stlckney's Observ. on the Gnib, 8vo. Hull, ISOO. VOL. II. K 202 RAVAGES OF INSECTS. Ovipositor and eggs of the crane-fly {Tipula). The eggs are exceedingly small and black, like grains of gunpowder, and each female lays a good many hun- dreds. The position which she assumes appears some- what awkward, for she raises herself perpendicularly on her two hind-legs, using her ovipositor as a point of sup- port, and resting with her fore-legs upon the contiguous herbage. She then thrusts her ovipositor into the ground as far as the first ring of her body, and leaves one or more eggs in the hole ; and next moves onwards to another place, but without bringing herself into a horizontal po- sition. The maggot, \vhen hatched from the egg, im- mediately attacks the roots of the grass and other herb- age which it finds nearest to it ; and of course the por- tion of the plant above ground withers for lack of nourishment. The maggots of this family which seem to do most injury are those of Tipula oleracea and T. cornicina. In the summer of" 1828, we observed more than an acre of ground, adjoining the Bishop of Oxford's garden at Blackheath, as entirely stripped, both of grass and every- thing green, as if the turf had been pared off from the surface, the only plant untouched being the tiny bird-tare MAGGOTS. 2Q3 (^Ornithopus perpusillus) . On digging here to learn the cause, we found these larvae already full-fed, and about to pass into pupae, after having left nothing upon which they could subsist. It was not a little remarkable that they seemed to be altogether confined to this spot ; for we did not meet with a single foot of turf destroyed by them in any other part of the heath, or in the adjacent fields. So very complete, however, was their destruction of the roots on the spot in question, that even now, at the dis- tance of two years, it is still visibly thinner of herbage than the parts around it. (J. R.) Reaumur gives a similar account of their ravages in Poitou, where, in certain seasons, the grass of the low moist meadows has been so parched up in consequence, as not to afford sufficient provender for the cattle. He describes the soil in Poitou as a black peat mould ; and it was 'the same in which we found them at Blackheath, with this difference, that the spot was elevated and dry. According to M. Reaumur, also, their only food is this sort of black mould, and not the roots of grass and herbage, which he thinks are only loosened by their burrowing.* This view of the matter appears strongly corroborated by the fact that several species of the family feed upon the mould in the holes of decaying trees, par- ticularly the larva of a very beautiful one (Ctenophora JIaveoIata, Meigen), which is very rare in Britain. It is proper to mention, however, that Mr. Stickney's ex- periments,! contrary to the conclusions of Reaumur, in- dicate that these larvae devour the roots of grass ; and Stewart says they " feed on the roots of plants, com, and grasses, and are thence destructive to gardens, fields, and meadows. They prevailed in the neighbourhood of Edinburgh, and other places in Scotland, in the spring of 1800, when they laid waste whole fields of oats and other grain." | In many districts of England these insects cut oflT a large proportion of the wheat crop, particularly, it would * Reaumur, v. 12, &c. f Obs. on the Grub. + Elements, ii. 267. k2 20 i RAVAGES or INSECTS. appear, when it had been sown on clover leys. " In the rich district," say Kirby and Spence, "of Sunk. Island, in Holderness, in the spring of 1813, hundreds of acres of pasture have been entirely destroyed by them, being rendered as completely brown as if they had suffered a three months' drought, and destitute of all vegetation except a few thistles. A square foot of the dead turf being dug up, 210 grubs were counted on it ; and, what iurnishes a striking proof of the prolific powers of those insects, last year it was difficult to find a single one."* It is worthy of remark that the mandibles of these de- structive creatures, which are claw-shaped and transverse, do not act against each other as is usual among insects, but against two other pieces which are immoveable, con- vex, and toothed, — as if the under-jaw in quadrupeds were divided into two, and should act vertically on tho two portions of the immoveable upper-jaw thrown in between them. The maggot of a minute fly of the same family, known by the name of the wheat-fly {Cec'idomyia Tn'tici, Kirby and Spence), is frequently productive of great damage in the crops of wheat. Its history was first investigated by Marsham, and subsequently by Kirby and Spence, and several other intelligent naturalists. The parent fly is very small, not unlike a midge {Cidicoidcs punctata^ Latr.), of an orange colour, and wings rounded at the tip, and fringed with hairs. f The female is furnished with a retractile ovipositor, four times as long as the body, and as fine as a hair, for depositing her eggs, M'hich she does in the glumes of the florets of the grain. The following account of its proceedings is given by Mr. Shireff, an intelligent farmer of East Lothian. " Wheat-flies," he says, " were first observed here this season on the evening of the 21st of June, and, from the vast number seen, it is probable a few of them may have been in existence some days previous. The * Iiitr. i. 318, note. f Linn. Trans., iii. 243— iv. 231-240 ; v. 96. MAGGOTS. * 205 eggs were visible on the 23rd, the larvce on the 30th of tliat month, and the pupae on the 29th of July, The flies were observed depositing eggs on the 28th, and finally disappeared on the 30th July ; thus having ex- isted throughout a period of thirty-nine days. " The flies were observed to frequent the wheat-plant, including the thicic -rooted couch-grass (Iriticiim i-epens). They generally reposed on the lower parts of the stems during the day, and became active about sunset, except when the wind was high. I have, however, seen them flying about on cloudy mornings, till seven o'clock ; and, upon one occasion, witnessed them depositing their eggs, in a shaded situation, at two in the afternoon. Their movements appear to be influenced by the rays of light, of which they seem impatient, being active when the sun is below or near the horizon : they frequent the most umbrageous part of the crop, and shun that which is de- ficient in foliage. *' The flies almost invariably preferred the ears emerg- ing from the vagina to those farther advanced, for de- positing their eggs on ; and as one side only of the ear is exposed when the plant is in this stage of growth, the other side generally remained uninjured. The fly de- serted the fields as the crop advanced towards maturity, and were found longest on the spring-sown portion of the crop. It seemed to feed on the gum adhering to the newly emerged ears ; and as there is a great diversity in the time of sowing wheat in this neighbourhood, and consequently of the ears escaping fiom the vagina, I attribute the unusual length of time it has existed this season, to the supply of food thus gradually furnished. " The fly deposits its eggs with much intensity, and may easily be taken when so employed. Upon one occasion, I numbered thirty -five flies on a single ear ; and, after carrying it a distance of a quarter of a mile, six of them still continued to deposit eggs. At another time, I placed a fly, then laying, between the face and glass of my watch, where it deposited several eggs, although invariably interrupted by the revolution of the moment hand. 206 ' RAVAGES or INSECTS. " The eggs of the fly are generally found in clusters, varying in number from two to ten, upon the inner chaff, in which the furrowed side of the grain is embedded, and are also occasionally to be seen in the interior parts of the flower and chafl\. The eggs are deposited by means of a long slender tube, and fixed with a glutinous substance possessed by the fly. A thread of glutinous matter frequently connects a cluster of eggs with the style, where the larvae seem to subsist on the pollen ; in one instance, fifteen eggs were numbered on such a thread, several of which were suspended on the portion extend- ing between the chaff and the style. The fly not only seems thus to provide a conveyance from the larvae to the style, but also food for their support. The anthers are prevented from leaving the style in consequence of being gummed down by the glutinous matter of the fly, and the pollen thereby detained for the use of the larvae, which otherwise would, in part, be carried out of the glumes by the expansion of the filaments, — known to farmers by the term bloom. In the exertion of gumming down the anthers, many of the flies are entangled in the vascules of the corolla, and thus become a sacrifice to their maternal affection. " The larvae are produced from the eggs in the course of eight or ten days : they are at first perfectly trans- parent, and assume a yellow colour a few days afterwards. They travel not from one floret to another, and forty- seven have been numbered in one. Occasionally there are found in the same floret larvae and a grain, which is generally shrivelled, as if deprived of nourishment ; and although the pollen may furnish the larvae with food in the first instance, they soon crowd around the lower part of the gerraen, and there, in all probability, subsist on the matter destined to have formed the grain."* Another intelligent observer, Mr. Gorrie, of Annat Gardens, Perthshire, found that by the first of August all the maggots leave the ears, and go into the ground Loudon's Mag. of Nat. Kist, Nov. 1829, j-. 450. MAGGOTS. 207 Germination of a <,'rain of wheat, a, the heart of the grain, the part devoured by the insect. 6, bag of the seed, c, the root, rf, vessels to convey the nutriment for the root, e, feathers conveying the pollen to fructify the seed. about the depth of half an inch, where it is probable they pass the winter in the pupa state.* It is interesting to learn that this destructive insect is providentially prevented from multiplying so numerously as it might otherwise do, by at least two species of ichneumons, which deposit their eggs in the larvi£. One of these {Encyrtits inserens, Latr.) is very small, black, and shining. The other {Platygaster Tipulce^ Latr.) is also black, with red feet, and a blunt tail. These have been frequently mistaken for the wheat-fly ; but as * Loudon's Ma^. of Nat. Hist., September, 1829, p. 324. 208 EAVACES OF INSECTS, Transformations of tlie wheat fly : a, the female fly magnified ; h, larvae, natural si/e, feeding; c, one magnilied. it has only two w ings, %vhile they have four^ the distinc- tion is obvious. In order to observe the jjroceedings of the ichneumons, Kirby placed a number of" the larvae of the wheat-fly on a sheet of white paper, and set a female ichneumon in the midst of them. She soon pounced upon her victim, and intensely vibrating her antennae, and bending herself obliquely, plunged her ovipositor into the body of the larva, depositing in it a single e^^. She then passed to a second, and proceeded in the same manner, depositing a single egg in each. Na}', when she examined one which she found had already been pricked, she always rejected it and passed to another.* Mr. Shireff repeated these experiments successfully, ex- cept that he saw an ichneumon twice prick the same jnaggot, which " writhed in seeming agony," and *' it was again stung three times by the same fly." He adds-. *• the earwig also destroys the larvae, three of which I successively presented to an earwig, which devoured them immediately."! Mr. Gorrie describes these ich- neumons as appearing in myriads on the outside of the car ; but as impatient of bright light, sheltering them- selves from the sun's rays among the husks. Our English naturalists were for many years of opinion, that the insect called the Hessian-fly, so destructive to wheat crops in America, belonged to the same family {Muscidce) with the common house-fly ; and Mr. Mark- • Linn. Trans, ut svpra. f Loudon's Mag. ut supra. WHEAT-FLIES. 209 wick, an intelligent naturalist, by a series of observations on a British fly {Chlorops pumilionis^ Meigex) whicli attacks the stems oF wheat, created no little alarm among ag-riculturists. Markwick's fly is less than a fourth of an inch in length, with dark shoulders striped with two yellow lines ; and the maggot is white. He ])lanted roots of wheat containing larvye in a small flower-pot, and covered them with gauze. Each stem produced one of the above flies. The crop of wheat attacked by this maggot, though at first it appeared to fail, turned out well in consequence of numerous side shoots. It is only the early wheat sown in October that is affected by it.* «, The Hessian-fly (Cecidomt/ia destructor) ; h, Markwick flj (Chlorop$ pu7nilionis\ magnified. It now appears that Markwick was altogether mis- taken in identifying his insect with the Hessian-fly {Cecidoynyia destntctor, Say), which has been accurately described by Mr. Say in the ' Journal of the Academy of Natural Sciences of Philadelphia' for 1817. It is a little larger than our wheat-fly, more slender in the body, has longer legs, and is not orange, but black and fulvous. The female deposits from one to eight or more eggs on a single plant of wheat, between the sheath of the inner leaf and the stem nearest the roots ; in which situation, with its head towards the root or first joint, the young larva passes the winter, eating into the stem, and causing it to break. t * Mag. Nat. Hist.. July 1829, p. 292. f Ibid., vol. i. p. 228. k3 210 KAVAGES OF INSECTS. The devastation committed by the Hessian-fly seems to have been first observed in 1776, and it was erroneously supposed that the insect was conveyed among straw by the Hessian troops from Germany. It was first noticed in the wheat fields of Long; Island, from which it spread gradually at the rate of fifteen or twenty miles round ; and in 1789 it had advanced two hundred miles from its original station in Long Island. Other accounts state that it did not travel more than seven miles annually, and did little serious damage before 1788. Their numbers seem almost incredible. The houses in the infested dis- tricts swarmed with them to so great a degree, that every vessel was filled with them ; five hundred were actually counted on a glass tumbler which had been set down for a few minutes with a little beer in it. They were observed crossing the Delaware river like a cloud ; and even mountains do not seem to interrupt their pro- gress.* We can well understand, therefore, that so formidable a ravager should have caused a very great alarm ; and even our own government was in fear lest the insect should be imported. The privy council, in- deed, sat day after day in deep consultation what mea- sures should be adopted to M'ard off the danger of a calamity more to be dreaded, as they well knew, than the plague or the pestilence. Expresses were sent oflT in all directions to the officers of the customs at the different outports respecting the examination of cargoes, — de- spatches were written to the ambassadors in France^ Austria, Prussia, and America, to gain information, — ■ and so important altogether was the business deemed, that the minutes of council, and the documents collected from all quarters, fill upwards of two hundred pages. f As in the case of the English wheat-fly, the American Hessian -fly has a formidable enemy in a minute four- winged fly (Ceraphron destructor, Say), which deposits its eggs in the larvae. Were it not for the Ceraphron, indeed, Mr. Say is of opinion that the crops of wheat * Kiiby and Spence, vol. i. p. 172. f Young, Annals of Agric, vol. xi. CHEESE-FLY. 211 would be totally annihilated in the districts where the Hessian-fly prevails.* Those who have, from popular associations, been ac- customed to look with disgust at the little white larvae common in cheese, well known under the name of hoppers^ will be somewhat surprised to hear the illus- trious Swammerdam say, " I can take upon me to affirm that the limbs and other parts of this maggot are so uncommon and elegant, and contrived with so much art and design, that it is impossible not to acknowledge them to be the work of infinite power and wisdom, from which nothing is hid, and to which nothing is impos- sible." f But whoever will examine it with care, will find that Swammerdam has not exaggerated the facts. The cheese-fly (Piophila Casei, Fallen) is very small and black, with whitish wings, margined with black. It was one of those experimented upon by Redi to prove that insects, in the fabric of which so much art, order, contrivance, and wisdom appear, could not be the pro- duction of chance or rottenness, but the work of the same Omnipotent hand which created the heavens and the earth. This tiny little fly is accordingly furnished with an admirable instrument for depositing its eggs, in an ovipositor which it can thrust out and extend to a great length, so that it can penetrate to a considerable depth into the cracks of cheese, where it lays its eggs, 256 in number. " I have seen them myself," says Swammer- dam, '' thrust out their tails for this purpose to an amazing length, and by that method bury their eggs in the deepest cavities. I found in a few days afterwards a number of maggots which had sprung from those eggs, perfectly resembling those of the first brood that had produced the mother fly. I cannot but also take notice that the rottenness of cheese is really caused by these maggots ; for they both crumble the substance of it into small par- ticles and also moisten it with some sort of liquid, so that * Jonrn, of Acad. Philadelph. vi supra. f Bibl. Naturae, vol. ii. p. Q'i. 212 KAVAGES OF INSECTS. the decayed part rapidly spreads. I once o>)served a cheese which I had purposely exposed to this kind of fly grow moist in a short time in those parts of" it where eggs had been deposited, and had afterwards been hatched into maggots ; though, before, the cheese was perfectly sound and entire." * The cheese-hopper is furnished with two horny clavr- shaped mandibles, which it uses both for digging into the cheese and for moving itself, being destitute of feet. Its powers of leaping have been observed by every one ; and Swammerdam says, " I have seen one, whose length did not exceed the fourth of an inch, leap out of a box six inches deep, that is, twenty-four times the length of its own body: others leap a great deal higher."f For this purpose it first erects itself on its tail, which is fur- nished with two wart-like projections, to enable it to maintain its balance. It then bends itself into a circle, catches the skin near its tail with its hooked mandibles, and after strongly contracting itself from a circular into an oblong form, it throws itself with a jerk into a straight line, and thus makes the leap. One very surprising provision is remarkable in the breathing-tubes of the cheese-maggot, which are not Cheese Ijoppers (Fiapkila easel. Fallen) a, the lYiagjB^ot extcndefl; b, in a leaping position ; d, the same magnified ; e, the fly maijnified ; f, (J, the fly, natural size. * Swammerdam, vol. ii. p. 69. f Bibl. Nat., vol. ii. p. 65. BLOW-FLIES. 213^ placed, as in caterpillars, along the sides, but a pair near the head and another pair near the tail. Now, when burrowing in the moist cheese, these would be apt to be obstructed ; but to prevent this, it has the power ot* bringing over the front pair a fold of the skin, breathing in the meanwhile through the under pair. Well may Swammerdam denominate these contrivances " sur- prising miracles of God's power and wisdom in this ab- ject creature." Like the other destructive insects above mentioned, the multiplication of the cheese-fly is checked by some insect, whose history, so far as we are aware, is not yet known. Swammerdam Ibund many of the maggots with other larvag in their bodies ; but he did not trace their transformations. If they were the larvae of an ichneu- mon, it must be exceedingly minute. It must have attracted the attention of the most in- curious, to see, during the summer, swarms of flies crowding about the droppings of cattle, so as almost to conceal the nuisance, and presenting instead a dis])lay of their shining corslets and twinkling wings. The object of all this busy bustle is to deposit their eggs where their progeny may find abundant food ; and the final cause is obviously both to remove the nuisance and to provide abundant food for birds and other animals, which prey upon flies or their larvae. The same remarks apply with no less force to the blow-flies which deposit their eggs, and in some cases their young, upon carcases. The common house-fly (Musca domestica) belongs to the first division, the natural food of its larvag being horse-dung; ccnsequently it is always most abundant in houses in the vicinity of stables, cucumber beds, &c., to which, when its numbers become annoying, attention should be primarily directed, rather than having recourse to fly-waters. Another common insect (Bibio Jiortulamis, Meigex) lives in the larva state in cesspools, along with rat-tailed larvae, &c. The maggot of the bibio is very peculiar in form. They are hatched from eggs with shells as hard as Paris plaster, deposited on the adjacent walls, and 214 RAVAGES OF INSECTS. frequently upon the pupa-case w hich the mother has pre- viously quitted. Like the larvae of the crane-flies above described, this one moves itself chiefly by means of its mandibles, and therefore it can make no progress on a piece of smooth glass. Its skin, it may be remarked, is so exceedingly hard and tough, that it is no easy matter to kill it.* We have introduced this insect here, how- ever, chiefly for the purpose of refuting an erroneous popular accusation against it, which is supported by the high authorities of Ray and Reaumur. Our great Eng- lish naturalist calls it the deadliest enemy of the flowers in spring, and accuses it of despoiling the gardens and fields of every blossom. f Reaumur is less decided in his opinion ; for though he perceived that, not being fur- nished with mandibles, they could not, as is supposed, gnaw the buds of fruit-trees ; yet, from their being found crowded upon flowers and buds, he thinks they may suck the juices of these, and thus cause them to wither.^ We are satisfied, by repeated observation, that the fly Transformations of Bihio Iwrtulanus, Mfigen. a, the egg inagnificd ; h, the same when hatched ; c, d, the maggot and pupa magnibcd ; e,J, the same, natural size ; g, the fly. * Swammeidam, x. 212. f Rail Hist. Insect. Pief. p. xi. % Reaumur, v. 56. BLOW-FLIES. 215 only uses its sucker (Jiaustellum) for sipping the honey of flowers, or the gum with which the opening bud is usually covered. The damage of which it is accused is more probably done by caterpillars, snails, or other night- feeding insects, which, not being seen by day, the fly is blamed for what it is entirely innocent of. (J. R.) In the case of the blow-flies Linnaeus tells us that the larvae of three females of Musca vomitoria will devour the carcase of a horse as quickly as would a lion ; and we are not indisposed to take this literally, when we know that one mother of an allied species (J/, carnarid) produces about 20,000, and that they have been proved by Redi to increase in weight two-hundred-fold within twenty-four hours. The most extraordinary fact illus- trative of the voracity of these maggots which we have met with, is the following, given by Kirby and Spence, from ' Bell's Weekly Messenger :' — *' On Thursday, June 25th, died at Asbornby, Lin- colnshire, "John Page, a pauper belonging to Silk-Wil- loughby, under circumstances truly singular. He being of a restless disposition, and not choosing to stay in the parish workhouse, was in the habit of strolling about the neighbouring villages, subsisting on the pittance obtained from door to door : the support he usually received from the benevolent was bread and meat ; and after satisfying the cravings of nature, it was his custom to deposit the surplus provision, particularly the meat, betwixt his shirt and skin. Having a considerable portion of this pro- vision in store, so deposited, he was taken rather unwell, and laid himself down in a field, in the parish of Scred- ington ; when, from the heat of the season at that time, the meat speedily became putrid, and was of course struck by the flies : these not only proceeded to devour the in- animate pieces of flesh, but also literally to prey upon the living substance ; and when the wretched man was acci- dentally found by some of the inhabitants, he was so eaten by the maggots that his death seemed inevitable. After clearing away, as well as they were able, these shocking vermin, those who found Page conveyed him to Asbornby, and a surgeon was immediately procured, 216 RAVAGES OF INSECTS. who declared that his body was m such a state, that ich as have rings for the finger and thumb, binding these with silk, or cotton to prevent their hurting the hand. To the blades of these, hoops should be fitted, covered with fine gauze, and made to close accurately when moved like a pair of scissors. It requires some experience and dex- terity to catch nimble insects with these ; but it is indis- pensable for a collector to acquire this skill. Without Riii'j-ncl. Net-forceps. opening them at all, the forceps may be used for securing an insect when alighted on a wall, or other flat surface, by merely covering it ; for which purpose some collectoi's also use a ring-net. We are of opinion, however, that it is more convenient to have few instruments, for multi- l)licity only serves to embarrass. We have taken a great number of insects by means of a pill-box, putting the lid on one side and the bottom on the other side of a leaf, and suddenly shutting in both the insect and the part of the leaf it was sitting on. Whoa a small moth, again, or other insect, is resting on a wall, a }>ane of glass, or the smooth trunk of a tree, we take 232 PRESERVATION OF INSECTS. a, French beetle forceps; and b, Pliers. off the lid of a pill-box, cover the insect with the bottom part, which we move backwards and forwards till the insect takes refuge from the annoyance at the very bottom, when we cover it as quickly as possible with the lid. This is by far the best way of taking small moths, for their delicate plumage is not injured, as it must in- evitably be when they are touched even in the most gentle way. We purchased last year, in Paris, a pair of insect for- ceps, which do not seem to be known to our collectoi*s, but which we have found exceedingly useful for taking beetles and other insects out of holes where they cannot be otherwise easily reached. The instrument is made of steel, and resembles a pair of large scissors. In some, the handle-rings are like those of scissors, on a line with the blades ; in others, they are at right angles to these. The pliers used by our collectors are much inferior in utility, being too small, short, and slender. The French instrument is farther useful for seizing venomous or dan- gerous insects. In other cases the fingers alone are often sufficient, and for minute beetles a wetted finger. In order to get at beetles and larvae which feed under the bark, or in the wood of trees, and also under ground, the instrument which we have found most convenient is DIGGEU. 233 a very strong clasp-knife : one which has a saw-blade, a hook, a file, and other instruments in the same handle, is preferable ; but most of the London collectors use what is called a digger, and first, if we mistake not, described by Mr. Samouelle, in his Compendium. It is made of steel, of from twelve to eighteen inches long, forked at the extremity, and fixed into a wooden handle. In addition to this, w^e recommend a long slip of very thin and narrow whalebone, which may be introduced into the holes of such insects as burrow in the earth or sand, to direct us in digging down to their nests, the hole being certain to be filled up, and probably lost, without such a contrivance. When a piece of whalebone is not at hand, a long straw will form a good substitute. Digger. When insects are caught merely for the cabinet, and not with reference to their habits and economy, collectors provide themselves with a quill-barrel, sealed at one end with wax, and having a cork stopper at the other, for very minute specimens ; with a wide-mouthed phial, containing weak spirits of wine, into which dark-coloured beetles, wasps, and bees, are put, the spirits instantly killing them, and preserving them for future purposes ; and with a pocket collecting box or boxes for winged insects. An oblong chip wafer-box, lined at top and bottom with cork, and covered with white paper, will form a very good collecting box, taking care that it is neither too shallow nor too deep ; but some have a square box, made of mahogany, deal, or cedar, with hinges on one side and a spring on the other, so that it can be opened by the left hand while an insect is held in the right, and figured above (Z*, p. 228). Sparmann, when travelling at the Cape, used to stick his insect specimens on the outside of his hat, to the consternation of the L 3 234 PRESERVATION OF INSECTS. Chip collecting box, oj ened. simple Hottentots, who took him for a conjuror. A more judicious plan is for a collector to have the crown of his hat lined inside with cork, which will save hin) the trouble of carrying a collecting box. When a col- lector has not his boxes with him, a bit of paper, twisted at each end, will often answer every purpose. When an insect is caught, before it be placed in the collecting box or the hat-crown, it is necessary to kill it, and this circumstance has given rise to much preju- dice, on the charge of cruelty, — the objectors forgetting that most of the insects so killed could not naturally sur- vive many days, and that their feelings of pain are, in all probability, much less acute than those of animals fur- nished with a brain and cerebral and vertebral nerves, of which they are destitute. Accordingly, a fly with- out its head will walk about almost as if nothing had happened to it, and a wasp will eat greedily with the head only when it has been separated from the body. We should not like, however, to be considered advocates of any species of cruelty, hoM-ever slight, and in killing insects for a collection the speediest methods are to be preferred. In the case of butterflies and some moths, as well as other winged insects, a slight pressure upon the breast will instantly kill them, and exposing them to heat is a still more rapid means, plunging those con- METHOD or SETTIXG. 235 tained in a phial into boiling water, and holding those in pill-boxes near the fire. Suffocating them with sulphur, as some recommend, spoils the colours ; and we re- marked in the museums of Brussels, Louvain, and Frank- tbrt-on-the-Maine, that all the insects had had their co- lours injured in this way, the black spots on white but- terflies being turned to brown, and the white tinged with yellowish green. In the case of insects tenacious of life, such as some moths, j^articularly females which Iiave not Setlingneedles and brush ; with the method of seUing insects, a, Swal« low-tailed butterfly (^Papiliu machaim) ; h. Wasp ; c. Beetle. 286 PRESERVATION OF INSECTS. deposited their eggs, piercing their breast with a pin dipt in nitric acid will instantly kill them. After killing dragon-flies the intestines must be carefully removed, otherwise the colours will all become black. Method of mounting smull insects. To fit insects for a cabinet, they require to be set, as it is termed ; that is, all their parts must be placed in the manner best fitted to display them. For this pur- pose each is pierced, when dead, with an insect pin, a fine slender sort, manufactured on purpose. Beetles ought to have the pins passed through the shoulder of the right wing-case, and butterflies and other insects through the corslet, on a right line with the head, and a little back from it. While the insect is fresh and flexi- ble, the legs and wings are to be stretched out with a setting-needle, or a large pin bent at the point and fixed into a wooden handle, then stuck upon a board covered with cork and paper, and kept in their proper position by means of pins and braces till they become dry and stiff". The braces are made with slips of fine card, or thick hot-pressed paper, stuck through at one end with a strong pin. When insects have become stiff before being set, they may be rendered flexible again by cover- ing them over for several hours with a damp cloth, which, however, must not be permitted to touch them. A camel-hair pencil is used for brushing off" dust. The mode of setting will be best understood from the figures. When insects are very small, as piercing them with a pin would destroy them, it is usual to gum them on a slip of card or cut wafer, and to arrange this in the cabi- SETTING-BOARD. 237 net. Minute beetles and flies may thus be preserved, as is shown in the figures. The setting-board ought to be kept where there Is a free ventilation of air till the set insects are thoroughly dry ; but it is necessary that it be also out of the reach of spiders ; for we have in several instances had our specimens, while drying, mutilated and destroyed by these prowlers. The most convenient apparatus is an upright box, with grooves, into which the setting-boards may slide, with the door and the side of the box opposite to it covered with gauze. Si'UiiiiC-bo ir |-3t' r. o OVin^-cassi Imecis.) S^ ;t3- 5-5 rafe , -> TRICHOPTERA. o-, I « ^ (liaity-icinsfd Insects.) g^ a- J 'megaloptera. \' "" ^TTERA. T^ 1/ Ringed Inseclt.) ^-t [/ ^ NET'ROPTERA. t^^ ,? ir' 1 s S (fciny-ii inged Imccls.J H.-^ 254 SYSTEMATIC ARRANGEMENTS OF INSECTS. Insects have also been divided according to the con- dition of their food ; but the arrangements on this prin- ciple have not, as far as we know, been perfected. I. Insects feeding on Living substances {Tliolei-o- phaga). 1. Feeding on living flesh (CV/r;u'i7ora). a, Feeding on aphides (Aphidivora). 2. Feeding on growing vegetables {Phytophagd). a, Feeding on grain and seeds {Granivora), b, Feeding on fungi (^Fiingivora). II. Insects feeding on Dead substances {Saprophaga). 1. Feeding on dead "wood (^Ligmvora). 2. Feeding on -dung {Coprophaga). 3. Feeding on dead animals {Neeropkaga). ( 255 ) ILLUSTRATIONS OF VOL. II. out by jet 1 Artificial hive for observing the mason-ants . 2 Vertical section for masou-ant s nest 3 Contrivance of mason-ants to ttrengthen the building of nest ....... 4 Artificial hive for the wood-ant . , . 5 Portion of a tree, with chambers, &c., chiselled ants ....... 6 Warrior ant in the winged state . • . 7 White ant queen distended witli eggs . . 8 Covered way and nest of the termites arboTum 9 Section of the hill nest of the termites bellicosi 10 Hill nest of the termites bellicosi . . 11 Turret nests of white ants .... 12 Leg and pro-leg of a caterpillar, greatly magnified 13 Caterpillar of the goat-moth .... 14 Interior structure of the cossus . . . 15 Side view of the silk tube .... IG !*ection of silk tube, magnified . . . 17 Labium or lower lip of cossus . . 18 Cocoons of the emperor-moth . . • 19 Cocoon of aictia villica ..... 20 Net-work cocoon ...... 21 Nest of puss-moth, inclosing five cocoons . 22 Winter nest of the social caterjiillars of the brownt 23 Winter nests of Porthesia chrysorrhaea . . 24 Pendulous leaf-nests ..... 25 Nest and order of marching of the processionary caterpill 26 Garden s])ider suspended by a thread from its siiinneret 27 Spinneret of a spider magnilied to show the spinnerules 28 Single thread of a spider, greatly magnified . . 29 Attached end of a spider's thread, magnified . 30 Geometric net of the garden spider .... 31 Nests of the mason spider ..... 32 The spider, mygale caementaria .... 33 The eyes, magnified ...... 34 Parts of the foot and claw, magnified . . 35 Triple-clawed foot of a spider, magnified . 36 Small berry-shaped galls of the oak-leaf . . 37 Ovipositor of gall-fly, greatly magnified. . 38 Gallfly, and mechanism of ovipositor, greatly magnified 39 Bedeguar gall of the rose, produced by Cynips rosse 40 One of the bristles of the bedeguar ot the rose, magnified 41 Artichoke gall of the oak-bud, with gall fly 42 L' afy gall ot dyer's broom . 43 Semi-gall of the hawthorn . 44 Woolly gall of the oak .... il motli heir PAGE 23 23 256 ILLUSTRATIONS. 45 Oak-apple galls, one cut open to show the vessel 46 Root galls of the oak .... 47 Woody gall ou a willow branch . , 4S Currant gall of the catkins of the oak . 49 Gall of the hawthorn weevil . 50 A plant louse, magnified 51 Galls produced on tlie leaves of the poplar, with forms of the insect, ten figures. 52 Leal' of the currant bush, bulged out by the Aphis 53 Shoot of the lime-tree contorted by the Aphis tiliae 54 Pseudo gall of the bramble . . 55 Pseudo galls of the hawthorn . 55 I'seiido gall on the Scotch lir . 57 Ovipositor of the breeze- fly . . 58 Grub of the breeze-fly, four figures. 59 Fly, maggot, and grub of the ox breeze-fly 60 Bumps or wurbles produced on cattle . 61 Viscera of the Cossus .... 62 Caterpillar of Vanessa urticre magnified 63 Intestinal canals of the caterpillar, pupa, and butle 64 Ravages of the biilT-tip calerpilLir . 65 Encampment of tlie caterpillar of the small Siberian crab ..... 66 Transfoimations of the Gamma moth 67 Saw-fly of the gooseberry 68 Numatus capreae on the osier, and Selandria ;i 69 Transformations of the grain moths 70 Tratisf)rmations of the honeycomb-moths 71 Transformations of the cockchafer 72 Wire-worm and click-beetle . . . 73 Zabrus gibljus and Melolontha ruficoriiis 74 Corn-weevil, magnified . . . 75 Nut and apple tiee beetles . . 76 hark mined in rays by beetle-grubs 77 Locust 78 Ovipositor and eggs of the crane-fly 79 Germination of a grain of wheat . 80 Transfoimations of the wheat-fly . . 81 The Hessian fly and the Markwick fly . 82 Cheese-hoppers ..... 83 Transformations of Bibio hortulanus . 84 Lace-winged fly and Sjrplms 85 Breeding-cage ..... 86 Larvae-box arid pocket collecting box 87 Water-net ... . . 8S Butterfly-net and clap-net . . . t9 Ring-net and net-forceps . . . 90 French beetle-forceps and pliers 91 Digger ...... 92 Chip collecti')g-box .... 93 Setting-needles and brush, with the method of setti 94 Method of mounting small insects 95 Setting-board frame .... on th the V bcs fly lie on 11 aid ects London: Printed by William Clowes and Sons, Stamford Street. PP'OPERTY .-rrw^^ERTY OF ^. R METCALP