Libraime ^ Jacques LECHEVALIER 12. Rue de Tovunion PARIS VI j^ JEx Lihris ^ f N. A. SAUCEROTTE. \ LIBRARY OF 1885- IQ56 LIST OF VOLUMES OF THE NATURALIST^S LIBRARY, IN THE ORDER IN WHICH THEY WERE PUBLISHED. I. HUMMING-BIRDS, Vol. I., Thirty-six Coloured Plates ; Avith Portrait and Memoir of Linn^us. II. MONKEYS, Thirty-two Coloured Plates; mth Por- trait and Memoir of Buffon. III. HUMMING-BIRDS, Vol. II., Thirty-two Coloured Plates ; with Portrait and Memoir of Pennant. IV. LIONS, TIGERS, &c.. Thirty-eight Coloured Plates ; with Portrait and Memoir of Cuvier. V. PEACOCKS, PHEASANTS, TURKEYS, &c.. Thirty Coloured Plates ; with Portrait and Memoir Oi Artstotlf VI. BIRDS OF THE GAME KIND, Thirty-two Coloured Plates ; Avith Portrait and Memoir of Sir Thomas Stamford Raffles. VII. FISHES OF THE PERCH GENUS, &c., Thirty- two Coloured Plates ; with Portrait and Memoir of Sir Joseph Banks. VIII. COLEOPTEROUS INSECTS (Beetles), Thirty-two Coloured Plates ; with Portrait and Memoir of Rae. IX. COLUMBID^ (Pigeons), Thirty-two Coloured Plates ; with Portrait and Memoir of Pliny. X. BRITISH DIURNAL LEPIDOPTERA (Butter- flies), Thirty-six Coloured Plates ; with Portrait and Memoir of Werner. XL RUMINATING ANIMALS; containing Deer, An- telopes, Camels, Sec, Thirty-five Coloured Plates ; with Portrait and Memoir of Camper. XIL RUMINATING ANIMALS; containing Goats, Sheep, Wu.d and Domestic Cattle, &c. &c. Thirty-three Coloured Plates ; with Portrait and Memoir of John Hunter. XIII. PACHIDERMATA, or Thick-Skinned Quadrupeds ; consisting of Elephants, Rhinoceroses, Tapirs, &c. &c., on Thirty-one Coloured Plates ; with Por- trait and Memoir of Sir Hans Sloane. LIST OF VOLUMES. XIV. BRITISH NOCTURNAL LEPIDOPTERA (Moths, Sphinxes, &c.). Thirty-two Coloured Plates; with Portrait and Memoir of Madam Merian. XV. PARROTS, Thirty-two Coloured Plates; with Portrait and Memoir of Bewick. XVI. WHALES, Thirty-two Coloured Plates ; with Portrait and Memoir of Lacepede. XVII. BIRDS OF WESTERN AFRICA, Vol, I., Thirty-four Coloured Plates; with Portrait and Memoir of Bruce. XVIII. FOREIGN BUTTERFLIES, Thirty-three Coloured Plates ; with Portrait and Memoir of Lamarck. XIX. BIRDS OF WESTERN AFRICA, Vol. II., Thirty-four Coloured Plates; with Portrait and Memoir of Le Vaillant. XX. BIRDS OF GREAT BRITAIN AND IRE- LAND, Part I., Thirty-six Coloured Plates ; with Portrait and Memoir of Sir Robert Sibbaxd. XXI. FLYCATCHERS ; their Natural Arrangement and Relations, Thirty-three Coloured Plates; ^vith Portrait and Memoir of Barox Haller. XXII. A HISTORY OF BRITISH QUADRUPEDS, Thirty-six Coloured Plates ; with Portrait and Memoir of Ulysses Aldrovandi. XXIII. AMPHIBIOUS CARNIVORA ; including the Walrus and Seals, and the Herbivorus Cetacea, Mermaids, &c,. Thirty-three Coloured Plates; ^vith Portrait and Memoir of Francois Peron, XXIV. BIRDS OF GREAT BRITAIN AND IRE- LAND, Part II., Thirty-two Coloured Plates; with Portrait and Memoir of William Smellib. XXV. DOGS, Vol. L, Thirty-three Coloured Plates; with Portrait and Memoir of Pallas. XXVI. HONEY-BEE, Thirty-two Coloured Plates; with Portrait and Memoir of Huber. XXVII. FISHES, Vol. II., particularly their Structure and Economical uses, &c., Thirty-three Coloured Plates ; Avith Portrait and Memoir of Salviani. XXVIII. DOGS, Vol. II., Thirty-two Coloured Plates; with Porti-ait and Memoir of Don Felix D'Azara. XXIX. INTRODUCTION TO ENTOMOLOGY, Thirty-eight Coloured Plates ; with Memoirs of Swammerdam and De Geer. THE NATUEALIST'S LIBRAEY. THE if 'g ILIlllAMY. mmT®m®iL©(BYo T©a,2 = EDINBURGH. W.UXIZARS. LONDOS- SAMUEL HIGBLEY 32. FLEET STREET. DUBLIS W CCKRY JtJSK^* C? THE NATURALIST'S LIBRARY, CONDUCTED BY SIR WILLIAM JARDINE, Bart. F.R.S.E., F.L.S., &c. &c. INTRODUCTION TO ENTOMOLOGY VOL. I. BY JAMES DUNCAN, M. W. S. EDINBURGH : W. H. LIZARS, 3, ST. JAMES' SQUARE S. HIGHLEY, 32, FLEET STREET, LONDON; AND W. CURRY, JUN. AND CO. DUBLIN. 1840. tDl.N'BURGH : PKINTiiD UY T. CONSTABLE, PRiNTSR TO HKR MAJESTY. INTRODUCTION ENTOMOLOGY COMPREHENDING A GENERAL VIEW OF THE METAMORPHOSES, EXTERNAL STRUCTURE, ANATOMV PHYSIOLOGY, AND SYSTEMATIC ARRANGEMENT OF THE CLASS INSECTS. ILLUSTRATED BY THIRTY-EIGHT COLOURED PLATES, WITH MEMOIRS OF SWAMMERDAM AND DE GEER. BY JAMES DUNCAN, M. W. S. EDINBURGH : W. H. LIZARS, o, ST. JAMES' SQUARE S. HIGHLEY, 32, FLEET STREET, LONDON; AND W. CURRY, J UN. AND CO. DUBLIN. 1840. ADVERTISEMENT FROM THE PUBLISHER. The readers of the Naturalist's Library are aware that the various volumes of the series hitherto devoted to Entomology, have heen occupied with the elucida- tion of particular Orders and Families. The volume which we have now the pleasure of presenting to their notice, contains a general exposition of all the Orders, the predominance being given to those which were not previously noticed. Ample details of ex- ternal structure, of the anatomy and physiology of the class insects, of the modes of systematic ar- rangement, &c. have likewise heen given, in order to render it a complete introductory view of the entire subject Our entomological series, there- fore, — already amounting to six volumes, — affords a pretty full and profusely illustrated view of this interesting department of zoology, one eminently calculated to gratify the laudable curiosity of those X ADVERTISEMENT. who seek to discover and admire the good and the beautiful in the works of nature. Our next publi- cation in this branch will be a volume on Exotic Moths and Hawk-moths, — an imperfectly known department of the subject, — for which drawings of new and splendid species are now in preparation by Mr. Westwood, to whose elegant pencil we have likewise, as will be seen, been largely indebted on the present occasion, in the volume which this ac- companies. The next volume of our work, which will form the thirtieth, yn[\ embrace the natural history of a very remarkable group of quadrupeds, and one with which the public are very little acquainted, namely, the Marsupialia, or Pouched Animals, by George Waterhouse, Esq. Curator to the Zoological Society, illustrated with nearly forty Plates from drawings by W. Dickes, Esq. an artist now first employed to contribute to the Naturalist's Library. These drawings have been made with great care and high artistical skill, from specimens which are to be found assembled only in the collection of the Zoological Society of London. It may be added that this will be the first attempt which has been made to give a complete history and representation of this very extraordinary race of animals. ADVERTISEMENT. XI We are likewise glad to announce another volume from the pen of an individual who holds such a high name in the scientific world. Colonel Hamilton Smith, the author of the two volumes of our work devoted to the history of the dog, &c. The volume alluded to will contain the history of the Equid^e, (Horses and the allied species,) the drawings being from his own admirable pencil. CONTENTS THE FIRST VOLUME. PAGB xMemoir of Swammerdam, 17 Memoir of de Geer, .... 59 Introduction to Ento:\iology, . 67 Anatomy and Physiology of Insects, . 125 Nutrition, ..... 12G Digestion, ..... 127 Respiratory System, .... 155 Tracheae or Air-tubes, .... 160 Adipose tissue, and Secretions, 164 Nervous System, .... 173 Reproductive or Generative System, . 188 Muscular System, .... 192 Muscles of the Head, .... 194 Muscles of the Thorax, 195 Systematic Arrangejient of Insects, . 199 Order I. — Coleoptera, .... 201 Order II.— Orthoptera, 206 Fam. Forficulidse, .... 218 Fam. BlattidfB, ..... 221 Blatta {Blaberus) Gigantea. Plate VII. Fig. 1. 225 B. Petiveriana. Plate VII. Fig. 2. 226 Fam. Mantidae, 226 Mantis {Harpax) Ocdlaria. Plate VII. Fig. 3. 232 Mantis ReUgiosa. Plate VIII. 233 CONTENTS. PAOK 234 235 237 238 242 243 10 curious insect figured on ])latc 12, together witli the eggs, carefully taken from specimens in the IJritisli Museum, by Jlenry lIoj)leY Wiiitc, " »-.... - ■ ■ otit on an immunica- i m possible Mantis (Deroplatys) Desiccata, West. Plate IX. Empusa Gonrjylodes. Plate X. Fig. 1. Envpusa Lohipes. Plate X. Fig. 2. Fam. Phasmidai, ..... Phasma Necjjdaloides. Plate XI. Phyllium Skcifolid. Plate XII. Plate XII.* Having been favoured with a drawing of the other sex of Esq. of Lincoln's Inn, we have given a representatioi accessory plate. tion till after the body of the work was printed ,0 did not receive this o])lignig .it was in the text to allude to it at the proper place Fam. Achetidse, ...... 244 AcMa Arachnoidcs. Plato VI. Fig. 1. . . 248 Fam. Gryllidse, 248 Acrida Viridissima. Plate XIII. Fig. 1. . . 252 Acrida Verrucivora. Plate XIII. Fig. 2. . . 253 Pterophjlla Oadlata. Plate XIII. Fig. 3. . . 253 Anostostoma Australasice. Plate XIV. . . 254 Fam. Locustidoe, ...... 255 Locusta Mi[jratoi-ia. Plate XV. Fig. 1. . . 256 Lociista Dm\ Plate XV. Fig. 2. . . . 257 Locusta Crktata. Plate XVI. Fig. 1. . . 257 Locusta Flava. Plate XVI. Fig. 2. . . . 258 Locusta Surinama. Plate XVII. Fig. 1. . . 258 Trujcalis Conicus. Plate XVII. Fig. 2. . . 259 Order III.— Ileraiptera. .... 2.')() Heteroptcra, ...... 270 ScuidUra Dispar. Plate XIX. Fig. 1. . . 271 Pentatoma Rutiians. Plate XIX. Fig. 2. . .273 Pentaioma {Raphir/aster) Iiuxirnatus. Plate XIX. Fig. 3. 273 Coreus {Syrtomastes) Paradoxus Plate XX. Fig. 1. 274 Cerhus Flaveotus. Plate XX. Fig. 2. . . 274 Anisoscelcs Ilymeniphira. Plate XX. Fig. 3. . 275 Homoptera, ...... '^70 Fam. Cicadidaj, . . .... 276 Cimda {Polyneura) Ducalis. Plate XVIII. Fig. 1. . 277 Cicada Pkheia. Plate XXI. Fig. 1- • • ^78 Cicada Septendedm. Plate XXI. Fig. 2. Fcm. . 278 CONTENTS. FtUgora Latemaria. Plate XXII. Fig. 1 . . Ful(/ora Castrem. Plate XXIT. Fig. 2. Fulyora Candelaria Plate XX III, Fig. 1. . FvJ,(jora Maculata. Plate XXIII. Fig. 2. Apliana Submacidata. Plate XXIV. Fig. 1. Memhracis Foiiata. Plate XXIV. Fig. 2. . Centrotl. Plate XXV. Order IV. — Ncuroptera, .... Lihellula Quadnmaculata. Plate XX VII. Fig. 1. LibeUula Portia. Plate XXVII. Fig. 2. Lihellula Atdlena. Plate XXIX. Fig. 1. LHjcllda Pulchclla. Plato XXIX. Fig. 2. . JEshna Grtmdis, Plate XXVIII. Fig. 1. . Neitioptera AiKjulata, West. Plato XXVII. Fig. 3. Stilbopterijx Cudalis. Plate XXVIII. Fig. 2. Order V. — Trichoptera, .... Phnjiianca Grandis. Plate XXX. Fig. 1. . Order VI. — Hymenoptcra, ... Fam. Tenthredinida', Cimbex Decem-AfuculcUa. Plate XXX. Fig. 2. AthaliaCentifolicB. Plato XXX. Fig. 3. Fig.4,Cateri Sireoc Gigas. Plate XXXI. Fig. 1. . Tremex 'Columba. Plate XXXI. Fig. 2. Joppa Pida. Plate XXXI. Fig. 3. . EpMaltes Manifestator. Plato XXXII. Fig. 1. Stepkanus Coronatus. Plate XXXII. Fig. 2. Pelidnus Politurator. Plate XXXII. Fig. 3. Order VII. — Lepidoptera, Order VII I. — Strepaiptera, Stt/lops Dalii. Plato XXXIII. Fig. 1. XenosPeekii. Plato XXXIII. Fig. 2. Order IX. — Diptera, .... Ctenophora Pcdinicornis. Plate XXXIV. Fig. 1. TiAanits Tropicus. Plate XXXIV. Fig. 2. . Diopsis Tchieumonea Plate XXXIV. Fig. 3. . Asilits {BlcpharoteSf West.) Abdominalis. Plate XX Fig.l Aoanihomera Immanis. Plate XXXV. Fig. 2. liar, XV. FAOa 270 283 283 284 284 285 285 287 21)1 291 292 292 293 293 294 294 29G 29() 307 311 312 313 .313 314 315 316 316 317 318 320" 321 321 327 328 328 329 331 I?i all Tliirty-ei he repaired to Leyden to take his degree. There he resumed his intimacy with the famous Van Home, under whom he had formerly studied. Aware of his extraordinary skill in such matters, this Profes- sor engaged him in a variety of experiments, and in forming anatomical preparations, for which he took care to supply him with abundance of materials ; and with such enthusiasm did the young physician prose- cute this congenial task, that he is said to have laboured both by night and day. It was on this oc- casion that he first injected the uterine vessels of a human subject with a ceraceous matter, a useful operation which he subsequently learned to perform with great accuracy and beauty. He now also be- gan to practice a new and excellent method of pre- paring delicate viscera for demonstrations, namely. MEMOIR OF SWAMMERDAM. 27 by blowing them up with air^ after being properly evacuated and cleansed^ an invention which developed and stiffened the parts as effectually as an injection of waxj while it did not render them opaque and confus- ed, as that substance is liable to do. He obtained his degree as Doctor of Physic on the 22d February, 1667, after a pubhc defence of his thesis on Respiration. On this production he again concentrated his attention, and after thoroughly re- vising and enlarging it, speedily committed it to the press. It was published in the March following, and dedicated to his friend and patron Thevenot. Like all this author's works, it is distinguished for its originality, and most of the statements made, are the result of patient observation and experiment. But many of its views were too much opposed to gener- ally received opinions, to be readily admitted ; and the occasional introduction of extraneous matter, laid the work open to objection. Among other attempts made to refute its doctrines, there was one by John Baptist Van Lamsweerde, more remarkable for acri- mony than talent, in a publication entitled, '^An Expiration of Swammerdam's System of Respiration." But the work contained so many valuable observa- tions and experiments, that it had no difficulty in withstanding these desultory, though spirited attacks, and ultimately took its place among those which have materially contributed to advance our know- ledge of animal economy. No fewer than three editions have been printed at Leyden, of the re- 28 MEMOIR OF SWAMMERDAM. spective dates 1667, 1679:, 1738, the two former in 8vo, the latter in 4to. All his scientific pursuits, however, were suddenly- interrupted in the course of this year by a severe attack of quartan ague, by w^hich he was so much reduced, that he was obliged to refrain, for a time, from all mental and bodily exertion. When able to resume his labours, they were directed to a sub- ject which had temporarily been superseded by other interests, but to which he always reverted with the ardour of a first affection, viz. the Anatomy of In- sects. An impulse was given to his zeal by the in- terest which men of rank and science now began to manifest in his investigations; and many of them visit- ed him to witness some of the arcana of nature re- vealed by his singular dexterity and penetration. Among the most eminent of his visitors, in regard to rank, was the Grand Duke of Tuscany, who had come to Holland, accompanied by Mr. Thevenot, partly with the design of examining whatever was most interesting in nature or art in that country. As this prince was a lover of natural history, Swammerdam was eager to gratify his curiosity, and made several dissections of insects in his presence ; demonstrating, among other things, that the forms of the perfect Butterfly can be detected in the Caterpillar, and actually extricating all its parts, and rendering them distinctly recognisable, — an operation of sufficient delicacy to evince his consummate address, and the perfection of his instruments. So much struck was the Duke by his ingenuity, that he tried to prevail MEMOIR OP SWAMMERDAM. 29 on him to accompany him to Italy, by offering to purchase his museum for twelve thousand florins, and assign him a residence at his own court of Flo- rence. But this generous proposal he did not hesi- tate to decline, both from an unwillingness to leave his native country, and submit to the restraint and change of habits which such a step would neces- sarily entail. His prosecution of the study of insects was now almost incessant. When occasionally diverted from it for a short time by inevitable occurrences, he again returned to it with redoubled ardour, and a perse- verance which seemed to know no relaxation. Of this we may judge from the fact, that in the year 1 669 — only two years after obtaining his degree, and notwithstanding the interruptions occasioned by his illness and numerous scientific avocations of a differ- ent nature — he published a General History of Insects ; a work of considerable extent and remark- able labour.* During its preparation he neglected, in a great measure, his professional prospects, and incurred no small expense in collecting insects from all quarters of the world. Hitherto he had been entirely dependant on his father in pecuniary matters, and the latter now began to intimate his disappro- bation of his manner of expending both his money and his time. He urged him to abandon pursuits which brought no remuneration, and betake himself * "Written in Dutch, and published at Utrecht in 4to. A French Translation appeared at the same place in 1682, and several Latin editions exist. 30 MEMOIR OF SWAMMERDAM. to the active and profitable duties of liis profession. The zealous student himself saw the propriety of acting on this advice, and it seems to have been his design to do so ; but he was so long in prevailing upon himself to forsake inquiries which aiforded him so much gratification and delight, that his father's patience became quite exhausted, and he declared that he would afford him no farther supplies of money — a resolution which he soon carried into effect. Thus thrown upon his own resources, Swammer- dam had no alternative but to turn his medical skill to account ; but the state of his health, which had been precarious ever since the illness mentioned above, and was still further impaired by unremitting study, proved inadequate to support the fatigue of such an employment. With a view to its restoration he retired to the country, and he had no sooner set- tled there than he relapsed into his former habits and studies. His generous friend Thevenot, upon becoming acquainted with his disagreement with his father, endeavoured to prevail on him to take up his residence in France, where he undertook to provide him with every thing requisite for caiTying on his favourite pursuits; but, owing to the opposition made by his father, this invitation was not accepted. Still anxious to conciliate his incensed parent, upon returning to Amsterdam, Swammerdam employed himself for a time in making what was supposed to be a final survey of their joint collection, and drawing up a catalogue of the objects it contained, a laborious MEMOIR OF SWAMMERDAM. 31 task, which he afterwards regretted that he had undertaken. During the years J 671 and 1672, his principal studies seem to have been more directly connected with his profession, for we find that he transmitted in that period to the Royal Society of London, a variety of plates representing the womb of a human subject, together with drawings of the spermatic vessels, tube of the womb, and ovaries. These were partly intended to illustrate his manner of making anatomical preparations, and filling both arteries and veins, even to their minutest ramifications, with a substance which preserved their primitive form and position. These were accompanied with a uterus pre- pared in the manner recommended. It was likewise his wish, by this communication, to vindicate his right, which had been disputed, to the discovery of certain facts regarding the spermatic vessels and the organs of generation. He was much engaged, also, at the period of which we now speak, in dissecting fishes, and making observations on their internal organs and their functions. The nature and properties of the pancreatic fluid, a subject which then excited much interest among physiologists, obtained a large share of his attention ; and he made some important discoveries regarding the nature and cause of hernia. In 1673, he subjected to his powerful microscopes a variety of ferns in order to examine the fructification, which was then little understood. Two congenial spirits. Grew* and jVIalpighi,t entered upon this * Anatomy of Plants, p. 200. t Anatomia PlantAnim, PI. 51, Fig. 299. 32 MEMOIR OF SWAMMERDAM. inquiry nearly at the same time^ and each of the three philosophers shewed that the dust on the lower surface of the leaves consists of an aggregation of small capsules, each surrounded by a jointed elastic ring, by the contraction and elasticity of which the capsules, when arrived at maturity, are opened with a spring, and the seeds (sporules) scattered to a dis- tance ; the whole exhibiting, Swammerdam remarks, the most wonderful construction that the mind of man can imagine, and so eminently displaying the con- trivance, order, providence, and wisdom of the great Author of all things, that, perhaps, a more striking specimen of these His adorable perfections is not to be found in any other part of the visible creation. The size of the capsules, he states, is so minute that they are almost invisible to the naked eye, it being scarcely possible to make a dot on paper, with the finest pencil, of so small dimensions. In each of these capsules he reckoned about forty-one seeds, which are, of course, invisible to the unassisted eye; to examine them, he fixed some to a hair of his head, and, in comparison, the hair appeared like the mast of a first-rate man-of-war ! He believes that there are more than sixty capsules in each little cluster ; consequently, at a very low calculation, every one of the latter will contain 2460 seeds. The reflec- tions with which our author concludes his remarks on this subject we shall here subjoin, both on ac- count of their intrinsic value, and as an example of that strain of sentiment and devotional feeling which pervades his writings. " You may hence con- MEMOIR OF SWAMMERDAM. 33 ceive/' (alluding to tlie minuteness of fern seeds, and the mechanism employed to disperse them,) "^ with what rapidity they may be wafted about by the wind, so as to account for these plants being found on the tops of the highest trees, and on walls, wherever they can find mould enough to take root in. '' The great obscurity of the human understanding is clearly proved by this observation, for, if it were not very dark indeed, how could it, during so many ages, deny that this plant had either seeds or flowers ? insomuch that it was one of the first errors taught young people in books, as well as heard in conversa- tion. We ought, therefore, to thank the Sun of divine grace, and true fountain of all useful know- ledge, that we are at last so happy as to attain more just notions of this matter. Should not this mistake teach us modesty in our opinions and our judgment upon many other occasions, seeing upon this the most penetrating geniuses have all gone astr^ ? If we are so liable to mistakes in regard to things that lie open to our inspection, what are we to say of our opinions of things that are invisible? How many idle notions are formed on such subjects ! how many senseless conceits, with which, however, we sometimes suffer ourselves so far to be deluded that we make nothing of injuring, both in character and person, those who happen to be of a contrary opinion ! It is. therefore, absolutely necessary that we should always distrust ourselves and act with the greatest circum- spection. In our present wretched condition, we are surrounded with ignorance on every side, and c 34 MEMOIR OF SWAMMEEDAM. have no other true knowledge than that of our own weakness and imperfections. Of ourselves we can do nothing, all we have we receive from the gracious hands of the Supreme Being, the munificent rewarder of good actions^ of whose divine favour I wish you uninterrupted enjoyment."* In the end of September, 1673, Swammerdam brought to a conclusion a work which had long oc- cupied his attention, on a subject admirably adapted to his peculiar powers. No one so deeply interested as he had been from his infancy in the general history of insects, could fail to be particularly struck "with the economy of bees, combining, as it does, much of what is most remarkable in other tribes of insects, with a great deal peculiar to itself. His efforts to become acquainted with their habits, and especially with their anatomical structure, have not been sur- passed in labour and perseverance by any subsequent enquirer. For months together he was accustomed to comilience his investigations at six o'clock in the morning, (when he could obtain sufficient light at that hour,) and continue them without interruption till twelve, seated all the time in the open air, with his head uncovered and exposed to the sun, the strongest light being necessary to enable him to use his magnifying glasses to the best advantage. About noon he was compelled to desist, as his eyes by that time began to fail from continual exposure to a bright light, and intent observation of minute objects through * Book of Nature, HilPs edition, Part II. p. 153. MEMOIR OF SVVAMMERDAM. 35 powerful glasses. The after part of the day, and usually no small portion of tlie night, were spent in registering his observations and writing out a detailed account of them, as well as in finishing his drawings. Such was his enthusiasm that he often used to wish that he had but one year of perpetual light and heat, to enable him to work without interruption. The whole of this laborious task, too, was executed while in a state of great bodily infirmity, and amid mental distractions arising from a cause to which we shall have immediate occasion to advert. Of the treatise resulting from these exertions, Boerhaave affirms, that al] the ages from the commencement of na- tural history to his time, have produced nothing equal — nothing to compare with it. It is, certainly deserving of the highest commendation for inde- fatigable research, minute and accurate descrip- tion, and elaborate delineations of internal organs. Indeed it may be said to have laid the foundation of an accurate and philosophical history of the Bee, and at the same time to have contributed largely to advance our knowledge of the structure of insects in general. When we consider how many interesting particulars Sv/ammerdam brought to light, it will not appear surprising that several singular facts escaped his observation. The comparatively ample knowledge we now possess of the subject is due to the accumu- lated labours of m-any different individuals, and it might have been much more limited than it is had it not been for the happy expedient of employing glass hives, a thing which had not been thought of in Swam- 66, MEMOIR OF SWAMMERDAM. merdam's time. His investigations placed future enquirers on a vantage ground which they could not otherwise have attained, and, had it not been for the discoveries of Swammerdam, we might have wanted many of those made by Reaumur, Huber, and others. So early as the year 1667 he had prepared and partly printed a treatise on the Ephemerus or Day-fly^ as he calls it, but it was not published till 1675. It first appeared in Dutch under the title of Ephemeri vita. He states that his principal object in lajdng it before the public was to give us wretched mortals a lively image of the shortness of human life, and there- by induce us, by frequent admonitions, to aspire to a better state of being. It accordingly abounds with pious reflections and meditations to such a degree that the subject by which they are suggested is, in some instances, almost lost sight of. In most of the translations which have appeared these portions are omitted, as well as the numerous Dutch sentences in prose and verse which he has liberally intro- duced. He traces with great care and assiduity the whole changes of the insect from the egg to the perfect state, in which it lives only four or five hours. The internal anatomy is also elaborately described and figured, constituting by far the most valuable portion of the work. The following remarks occur towards the close : — " All of these insects die in the very short space of time just mentioned, nor do any of them, — which is a matter very worthy of observation, — die a natural death on land ; all of them invariably go to the water again, after they have MEMOIR OF SWAMMERDAM. 3? gone througli the second change of their skin. God, therefore^ the Supreme Artist, has been pleased to assign this insect a short life that surpasses adoration. "Who has so great a genius, or is so conversant in the art of writing, as to be able to describe with a due sense, the trouble, the misfortunes this creature is subject to during the short continuance of its flying life ? For my part, I confess I am by no means able to execute this task, nor do I know whether nature ever produced a more innocent and simple little crea- ture, which is, notwithstanding, destined to undergo so many miseries and horrible dangers. " Besides that the life of the Ephemeras is short, nay, amazingly and incomprehensibly so, an infinite number of them are always destroyed in the birth, being devoured by fish. Nor does Clutius acquit any species of fish of this barbarity, except the perch and pike. Though the rest of the ephemeri have escaped this cruel danger, yet on land, when they ai'e engaged in the great work of changing their skin, they are barbarously devoured by swallows and other birds. Nay, if they escape this danger, when they afterwards approach again to the surface of the water, and carelessly sport and play there with their wings and tails, they a second time become a prey to the fish, which drag them away to the dark bottom of the water, and devour them. If they fly higher into the air, another kind of torment attends them, for then they are persecuted with a different barbarity, by other kinds of birds, which tear their limbs asunder, and devour them. Though these insects 38 MEMOIR OF SWAMMERDAM. tlien are the most innocent^ perhaps^ of all others, they are more cruelly treated or used, than the most mischievous of wild heasts. " As the ephemerus abounds with useful lessons and moral precepts, so it affords sufficient matter for various speculations. It is engendered, grows to its bigness, and then generates, lays eggs, casts its sperm, grows old, and dies in the space of five hours. This short space comprehends the morning, noon, and evening of its life."* The species on which Swammerdam made his ob- servations is the largest known, and is the Ephemera longicauda of Olivier {Enc^clop. Method. Art. Eijhe- mera.) In honour of the individual who made us so accurately acquainted with its history, Latreille subse- quently named it E. Swammerdiana. It is not a native of this country, but occurs in the larger rivers of Holland, Germany, and France. About the same time, he investigated in a similar manner the history and anatomy of what he names the asilus or gad-fly, but which is a dipterous species of the modern genus Stratiomys, or chamaeleon fly. His attention had been probably attracted to this insect, by the singular breathing apparatus of tlie larva, which consists of an anal orifice surrounded by a circle of diverging rays of beautifully feathered plumes. This singular structure, and the elegant appearance of the respiratory appendage, has caused it to be often described and delineated in modern •Book of Nature, Hill's ed. -.vhere will be found a synopsis of the Vita Ephemeri. MEMOIR OF SWAMMERDAM. 3D works, but Swammerdara's figure greatly surpasses all that have subsequently appeared (See Biblia Naturce, pi. 39.) It was figured before his time, both by Goedart and Aldrovandus, the former of whom called it the chamaeleon, from having kept an individual alive for nine months without food ; the latter names it the water intestine. Both were unacquainted with its metamorphosis, and nearly all its most remarkable peculiarities ; Swammer- dam's account leaves little to be desired. He was so much struck with the beauty of its parts, and their exquisite adaptation to the functions they per- form, that he frequently breaks out in lamentations of his own inadequacy to examine them aright, and in adoration of the power and goodness which they so signally manifest. " God, thy works infinitely surpass the reach of our feeble understandings ; all that we actually know of them, or ever can know, is but a faint and lifeless shadow of thy adorable perfections. The brightest understandings fail in the contemplation of them, and are obliged to con- fess, that all this boasted penetration is but short sightedness, when employed in fathoming the depth of that power, goodness, and wisdom, it has pleased thee to exert in the lowest part of thy creation. ^' The transformation from a worm to a fly, ob- servable in this insect, presents us with a real mira- cle, and may justly be considered, as a laying down of old worn-out parts, and an acquisition of new perfect ones instead of them ; in fine, as a total change of an old to a new, and of an imperfect to a 40 MEMOIR OF SWAM-MERDAM. perfect body, infinitely surpassing the utmost stretch of human understanding. As for my part, I dare boldly affirm, that the incomprehensible greatness of the deity manifests itself in these mysterious opera- tions in a particular manner, and affords us an opportunity of examining, as it were, with our senses, the divine nature."* Long before the period when these and other valu- able investigations of a similar kind were undertaken, a notable change had taken place in Swammerdam's mind, which led him to regard sucli pursuits in a very different light from what had been customary to him. He had always been of a devotional frame of mind, and this feeling was gradually deepened by observing the w^onderful instances of design, power, and goodness, which his studies so abundantly sup- plied. Hence his anxiety to direct the attention of the reader, on all fitting occasions, to the Almighty Author of all the wonders his penetration enabled him to re- veal, and to awaken those sentiments of devout adora- tion which they are so well fitted to inspire. But an event happened, apparently in the year 1672, which corrupted the source from which these feelings flowed, diverted them into a wrong channel, and ultimately brought his mind into a state of the most deplorable fanaticism. The immediate cause of this was the perusal of the works of Antoinette de la Porte Bourignon, a wild enthusiast, who was then using every effort to propagate her doctrines. She was a *BookofNat.n. 51. MEMOIR OF SWAMMERDAM. 41 native of Lisle in Flanders, a member of an opulent , family, from which she fled in order to avoid a mar- riage which they were desirous for her to contract. Her turbulent disposition, in connection with her objec- tionable tenets, so disturbed the community where- ever she took up her residence, that the civil autho- rities had usually to interfere, and compel her to change her abode. Her doctrines nearly correspond to those of the Mystics, and are explained in a work entitled the " Light of the World," the leading principle of which is, that the Christian religion con- sists neither in knowledge nor practice, but in a certain internal feeling and divine impulse, which arises immediately from communion with the Deity.'"' * One of the most influential of Bourignon's followers was a person named De Cordt, owner of a portion of the island of Holstein, who, at his death, made her his heir. She kept her wealth, however, to herself, under the pretence that she could find none worthy of her bounty ! Although there is little doubt that her intellect was disordered, she was certainly possessed of considerable talent. She could write French, Dutch, and German, almost with equal facility, and her religious compo- sitions were so numerous as to afford employment for a print- iAg press kept in her own house. She died at Franeker in 1680. Her disciples, who assumed the name of Bourignonists, became more numerous after her decease ; and one of the most celebrated of them, a Cartesian named Peter Poiret, attempted to reduce her works to a system, which was pub- lished at Amsterdam in 1686, under the title of " L'CEconomie Divine, ou Systeme Universel." Her opinions, at one time, excited a good deal of discussion in Scotland, and notwith- standing their extravagance, found not a few supporters. See Mosheini's Ecd. flist. V. p. 514, ^r. 42 MEMOIR OF SWAMMERDAM. These opinions S^yammerclam appears to have adopted in their utmost extent, and their effect on his melancholic temperament was such as to produce a completely morbid state of mind. The studies in which he had taken greatest delight, now began to appear odious to him. It was with the utmost diffi- culty that he could allow himself to finish his favourite work on Bees, and no sooner was it completed than he put it into the hands of another, without giving himself the least concern what might become of it. His inclination urged him strongly to continue his pursuits, but he now thought them incompatible with his duty to the Creator, as he alone, and not his creatures, wns worthy of engrossing all his love and regard. All worldly interests, accordingly, were soon despised and abandoned, and he devoted him- self wholly to the performance of the duties of re- ligion, accordinof to the erroneous notion he had formed of them. Every step he took was by the advice and authority of Antonia Bourignon, and she took care not to endanger the influence she had acquired over him, by allowing him to resume his former occupations, or engage in the ordinary busi- ness of life. His condition was rendered more de- plorable and hopeless, by a return of his former com- plaint, quartan ague, in greater severity than ever, (M?casioning such a prostration both of mental and bodily powers that he was for a time unfit for any kind of exertion. He now resolved to -withdraw entirely from the world, and spend the remainder of his days in solitary meditation. Before taking this MExMOIR OF SWAMMERDAM. 43 step, however, sufficient prudence still remained to lead him to consider what means he possessed of supporting himself in his retirement. His father could not be expected to afford facilities for carrying such a mistaken scheme into execution, and the only disposable property of any value he himself pos- sessed, was his museum. That, accordingly, he re- solved to sell, and he applied first to Thevenot, to make his intentions public, and to endeavour to pro- cure a purchaser. This was readily undertaken by his friend, but notwithstanding his utmost exertions he was unable to get it disposed of. In this disap- pointment, he made a similar application to Nicholas Steno, who was now settled at the Court of Florence, where he had become a convert to the Catholic re- ligion, and had been raised to a bishopric — a dignity likely to have the effect, if it was not conferred with the design, of making him stedfast in his new faith. Swammerdam thought that through his re- presentations, the Grand Duke might be induced to renew the offer he had formerly made for the collec- tion. The bishop of Titiopolis, in reply to his commu- nication, urged him very strongly to come to Florence with his collection, assuring him that the Duke would willingly give the priceformerlyoffered, as well as pro- vide for his comfort otherwise ; and, with the presump- tuous zeal of a new convert, he took advantage of the opportunity to press him with every argument to fol- low his own example, and conform to the church of Rome. The implied condition that Swammerdam was to accompany his museum to Tuscany, if pur- 44. MEMOIR OF SWAMMERDAM. chased by the Duke — a step which he never could bring his mind to — immediately put an end to any chance of disposing of it in that quarter ; and he wrote an indignant reprimand to his venal friend for venturing, in reference to his religious profession, to make a proposal to him which would at any time have been considered offensive, but which, in the present state of his sentiments, he regarded with un- qualified abhorrence. While measures were in pro- gress for the sale of his museum, he occasionally employed himself — notwithstanding his conviction of the sinfulness of allowing any secular pursuits, even in- cluding those of science, which may be said to be the best and purest, to distract the mind from uninter- rupted meditation on the Supreme Good, and the concerns of a future life — in further arranging and improving its contents, especially with a view to ren- der the many delicate preparations it contained as durable as possible, and thus increase their value in the event of a sale. Swammerdam's intercourse with Bourignon had hitherto been confined to epistolary correspondence, but he now conceived it essential to his happiness that he should have a personal interview with her, and for this purpose he repaired to Sleswick in Hol- stein, where she then resided. He staid for some time in her house, and became ere long one of her favourite adherents. An opportunity soon occurred to afibrd a proof of her confidence in him, and the •sincerity of his attachment. The Lutheran divines of Holstein, taking alarm at the pernicious principles MEMOIR OF SWAMMERDAM, 4,5 and proceedings of tills enthusiast^, were devising measures to have her expelled from the province,, and on becoming aware of their intention, she wished to take shelter in the king of Denmark's dominions. Swammerdam, and another disciple, were appointed to visit the Danish court, to ask permission to make this change of residence — a commission which he readily undertook. He accordingly set out for Copen- hagen, on the 25th March 1676; but was wholly unsuccessful in his object. He returned to Sleswick to give a report of his reception, and after a short residence there, went back to Amsterdam. His prospects in that city had not improved in his absence ; his father, whose resentment had been somewhat mitigated of late, was irrecoverably alien- ated from him by his recent imprudence. His sister Joanna, too, who had resided with his father since his wife's death, and often interceded with him on her brother's behalf, had just been married; and his father having resolved to live henceforth with his son-in-law, Swammerdam found himself at last de- prived of a home. In this exigency, two hundred florins a-year allowed him by his father, was all that he had to depend upon, and this being inadequate to defray his necessary expenses, he was obliged to think of some plan for relieving his necessities. A gentleman of rank, John Ort of Nieuwenrode, Breukele, &c., who had been long on terms of intimate friendship with Swammerdam, had often entertained him at his country-seat, and even proposed that he should take up his residence there altogether, that 4G MEMOIR OF SWAM.MEllDAM. lie might be able to pursue his scientific enquiries without molestation. He now intimated to this gentleman that it would be convenient for him to accept of this offer; and his mortification was not slight at receiving a direct refusal. Whether Ort had been insincere in his original offer ; whether cir- ciimstances had so changed as to render Swammer- dam's presence inconvenient^ or that the latter's peculiar habits, and extravagant religious notions, might be thought likely to make him not a very desirable inmate, it is useless to enquire : instances of similar treatment, from mere caprice and want of feeling, are too common to render any other expla- nation requisite. In the midst of these perplexities our author's father died, an event which relieved him from any immediate inconvenience arising from the insensibility of his reputed friends ; it even held out to him the agreeable prospect of a competency to live according to his inclinations, without the anno3'^ance of any professional drudgery, to which he always entertained a strong dislike. But, when the museum came to be disposed of and his father's property divided, these prospects were by no means realised. His sister claimed more than was rightly her due, and took the chief management of the sale, an exercise of authority to which Swammerdam submitted for the sake of peace, and that he might sooner enjoy the retirement and repose on which his heart was set. But even this surrender of his just rights was far from exempt- ing him from annoyance ; and the vexations attending MEMOIR OF SWAM MERDAM. 47 the family strife that ensued, together with the anxiety he continually felt about his spiritual state, and his almost unintermitted devotional exercises, again brought on a severe disorder of that description called a double tertian ague. During this long- continued illness, he was mostly confined to bed, and unfit for any exertion ; even when it was so far abated that air and exercise became desirable, he could not be pre- vailed on to leave his bed-chamber. In order to avoid the importunity of his friends on this subject, he persisted for a long time in maintaining an obstinate silence. In this moody and hypochondriacal state of mind, when any one attempted to draw his attention to the investigations which he formerly delighted in, he manifested great dissatisfaction, and even seemed as if he would feel relief by getting completely rid of the objects which he had taken such pains to collect and preserve. A final, offer of them was made to Thevenot, that he might dispose of them in France, accompanied with an intimation, that, if he should succeed, Swammerdam would accept of his invitation to come and live with him, provided he were allowed to do so retired and unknown. Thevenot, however, was unsuccessful ; and, as he now despaired of finding a purchaser for the entire collection, he determined to sell it by auction in separate lots, for such sums as might be offered. The sale was advertised to take place in the month of May, 1680. With whatever indifference Swammerdam might now regard his collection, he was not destined .to witness its dispersion. His disorder returned with 48 MEMOIR OF SWAMMERDAM. greater virulence than ever^ accompanied with symp- toms which he could not misinterpret. A slow and continued fever was gradually drying up the sources of life ; his countenance became cadaverous, his legs, feet, and belly swollen, and his whole body was racked with continual pains. On becoming acquainted with his condition, Thevenot sent him the Jesuits' bark, then supposed to be of great efficacy in curing fevers ; Swammerdam desired him also to send some specific against the drops^^ if he knew of any such. Finding himself grow gradually worse, he ceased entirely to speak of worldly concerns, and was unremitting in his preparations for the great change that w^as rapidly approaching. It took place on the 17th February, 1680. On the 25 til January of the same year, -when he found himself in such a condition as to leave no hopes of recovery, he had made his Avill, by which he be- queathed to Thevenot, the friend so often mentioned in the course of this sketch, all his original manuscripts relating to the history of bees, butterflies, &:c. along with fifty-two plates which had been engraved from his drawings. He ordered, besides, a collection of valuable papers on scientific subjects, then deposited in the house of Herman Wingendorp, at Leyden, to be delivered to the same person within a year after his death. Madam Volckers, wife of a physician named Daniel de Hoest, was made his heiress; this lady was also appointed his executrix, jointly with Christopher Van Weyland, but the latter dying soon after, the trust devolved entirely into her hands. MEMOIR OF SWAMMERDAM. 49 The papers just mentioned had been entrusted to Wingendorp in order that he might translate them into Latin. Swanimerdam is said to have had but little facility in the use of that language, although it was the usual medium of communication among learned men at that period ; it is certain that he wrote all his works in Dutch, and afterwards employed others to translate them, that they might not labour under the disadvantage of being in a local and unpopular tongue. The translator, in this instance, being needy and unprincipled, tried to make a property of the manuscripts in his possession, and refused to deliver them up to the executors. Upon this, a tedious law-suit ensued, and it was not till May, 1682, that the legatee had them placed at his disposal. It was his purpose to have them published immediately in Dutch, but probably finding that they required revisal, he caused them to be sent to France. He appears to have attempted some alterations and im- provements, a task for which he was probably indif- ferently qualified, but his death took place before he had them ready for publication. After Tlievenot's decease, they were purchased by Jubert, painter to the King of France, whose heirs afterwards sold them, for fifty French crowns, to a distinguished anatomist, Joseph du Verney. This individual for a long time disregarded them, but the anatomy of the articulated animals happening to come more into repute, he pro- posed to turn them to account in a work on insects under his own name, but of which they were designed to form the principal materials. On hearing of this .50 MEMOIR OF SWAMMERDAM. intended publication, Boerliaave sent to Paris to ascer- tain more precisely its nature, and learning that it was to contain Swammerdam's researches, he conceived the laudable desire of asserting his countryman's right to the honour of the discoveries about to be made known to the public. By means of two friends residing in Paris, this eminent man succeeded in obtaining pos- session of the entire manuscripts, together with the drawings necessary for their elucidation, at the price of 1500 French florins. This was in the year 1727. " As soon as I had got them," he says, " I read them, and, having diligently examined them more than once, I carefully digested them, and had the satisfac- tion of seeing that nothing was wanting except a few pages of the text in the treatise on bees, which a note on the margin observed was not to be repaired ; however, on looking narrowly for them, I had the good fortune of finding them elscAvhere. Upon this I would have published them directly, but for the insatiable avarice and unbounded audaciousness of the printers, who make nothing of reprinting things as soon as they appear, to the great loss of the first publishers ; however, I have at last succeeded in guarding against such foul treatment, and return my hearty thanks to all those who so generously contri- buted their assistance on this occasion. And now I must own, that it is with the greatest pleasure I find myself enabled, by this valuable work, to challenge all those nations who so liberally reproach us Dutch- men with a dulness that requires the inventions of others to sharpen it, to produce, before able judges. MEJIOIR OF SWAMMERDAM. 51 any thing to equal this performance of one of our countrymen. This instance will^ I believe, be suffi- cient to convince mankind that we have among us uncommon geniuses, who have made the most im- portant discoveries, and, spider-like, have furnished themselves alone both with the workmanship and materials. However, I must in justice own, there is now in France such another bright sun, who by his light not only shows, but adds grace and dignity to every object he is pleased to shine upon. I mean that prodigy of our age and glory of his country, the illustrious Reaumur. God grant this great man life to go through, and many years to survive, his great undertaking." '^ These valuable remains were thus secured for the benefit of science, and rendered accessible to all in the well-known work entitled Biblia Naturce sive Historia Insectorum in certas classes redacta, Sj-c. Sfc. This work was originally published at Ley den in 1737, with the text in the original Dutch, and a Latin translation by Professor Gaubius of Leyden. It is known to English readers by a translation from the pen of Thomas Flloyd, which was revised and improved by the addition of notes from Reaumur and others, by Sir John Hill, M.D., and published in a folio volume at London, in 1758. Several of the papers in this volume have been already referred to, and it is so well known that it is quite unnecessary to give any further account of its contents. Besides * Book of Nature, Hill's Edit. p. 14. 52 MEMOIR OF SWAMMERDAM. the investigations relating to insects, wliicli compose the greater portion of the work, there is a lengthened account of the snail, {Helix,) explaining its anatomy, mode of propagation, &c., a treatise on the generation of the frog, on the anatomy of the cuttle-fish, &c. The manner in which Swammerdam treats of the arrangement of insects into classes, is, as might he expected, not a little defective. But he was cer- tainly the first that assumed metamorphosis as the basis of a natural system, and in so doing, merits high approbation. He, referred all to four classes of metamorphosis, which, translated into the modern language of entomology, may be expressed as follows : 1 . No metamorpliosis. The animal changes its skin, but pre- serves its primitive form ; as in Aru- nea, Pulex, Mp-iapodes. In short the Aptera of Linnaeus. 2. Metamorpliosis. a. Incomplete. Animal active during itd whole life : at first without wings ; acquires rudiments of them in the nymph, and they become complete in the imago. Neuroptera^ Orthop- tera^ Hemiptera. h. Complete. Animal immoveable in the nymph state, but possessed of limbs. Hymenoptera, Coleoptera., Lepidoptera. c. Coarctate. Animal without limbs, and incapable of motion in the nymph state. Diptera^ The science of insect anatomy, as well as of some other tribes of animals related to insects, may almost MEMOIR OF SWAMMERDAM. 53 be said to have originated with Swammerdam. His intimate acquaintance with human anatomy, which had made considerable progress before his time, prepared him to enter upon the enquiry in the most intelligent manner ; and the sagacity, penetration and zeal with which he pursued it, are not a little remarkable. In the latter quality especially, he scarcely ever had an equal: no difficulties could deter, no disappointment discourage, and scarcely any degree of labour exhaust him. His enquiries were frequently carried on for a length of time together, with little interruption, both by night and day, without allowing himself the requisite time either for taking food or natural rest. When the subject occupied his mind, it did so almost to the entire exclusion of every thing else. His profession was neglected, his father's displeasure disregarded, his health sacrificed. This exclusive engrossment was certainly in him in some degree of a morbid nature. His constitution and temperament strongly predisposed him to that kind of enthusiasm which is allied to a species of mania. By sedentary habits, and the prevention of that wholesome play of the faculties produced by an alternation of pursuits, he aggravated the disorders to which he was na- turally liable, and brought on a state of dejection and hypochondriasis, which cast a shade over a large portion of his life. To this cause, also, ought to be ascribed, in no small degree, the mistaken views he adopted regarding religious duty ; his no- tion that it \A'as incompatible with the ordinary 54 MEMOIR OF SWAMMERDAM. business of life; and numerous other errors^ from which his good sense and general intelligence, if left to themselves, would have sufficed to preserve him. After his death, his museum was offered for sale for five thousand florins ; but no one appearing to give even that sum, so far below its real value, it was disposed of in small lots. It was thus completely dispersed, and lost for ever to men of science. The anatomical preparations were very numerous, and he had carefully preserved every thing relating to his entomological and other investigations, that he might have them to appeal to as unquestionable vouchers of the truth of his statements. He had collected about three thousand different species of insects ; many of the kmds occurring in his neighbourhood he had preserved in their various states, having been accus- tomed to hatch the eggs artificially, and watch the progressive changes of the larvae that spring from them. His instruments, microscopes, &c., shared the same fate with the objects on which they had been employed. Boerhaave deposited the manu- scripts and drawings which came into his possession, and furnished him with materials for the Biblia Na- turae and an account of its author's life, in the public library of the University of Leyden, that they might remain as a monument to the talents and zeal of his distinguished countryman. Considerable curiosity must naturally be felt to become acquainted with the means adopted by this lynx-eyed anatomist to effect those beautiful dis- coveries which distinguish his name so highly above MEMOIR OF SWAMMERDAM. 55 all his predecessors in the same field of lahour ; and this feeling we are in some measure enabled to gra- tify by the care of his biographer, Boerhaave_, whose account is so satisfactory, that we cannot do better than nearly translate his own words. For the dis- section of very minute objects, he had a small brass table, ingeniously constructed by an artist of Amster- dam, to which were attached two moveable brass arms. The upper part of these arms was so planned as to admit of a vertical motion, so that the operator could adjust their height to answer his purposes ; one of them was designed to hold the object under exa- mination, the other, the glasses through which it was to be viewed. These glasses were, of course, in great variety, as well as the manner in which they were fitted up into microscopes, and it was always a matter of great anxiety with Swammerdam to obtain them of the best possible substance and workmanship. It was his practice first to view tbe object under exami- nation through a glass of comparatively small power, and to apply stronger ones gradually as he was be- coming more familiar with its forms and appearance, a practice by which every observation was made subservient to the next, and the deceptive tendencies of different lights in a great measure guarded against. His skill and patience in constructing cutting instru- ments were remarkable, and it is, in a great degree, to their ingenious forms, and extreme delicacy, that much of his success is to be ascribed. His scissors were remarkably fine and sharp-pointed, and this was a favourite instrument with him, as he found it 56 MExMOIR OF SWAMMERDAM. separate a membrane equably, without the laceration or disorder which a single edge, however sharp, is apt to produce in delicate substances. These, as well as his variously formed knives, lancets, styles, &c., were so small and fine, that he could not sharpen them without the aid of a microscope. He employed to very great advantage, and with a dexterity entirely his own, slender glass tabes, sometimes no thicker than a bristle, and of a similar shape, being wide at the one end and tapering to a point at the othei-, to blow up the smallest vessels discovered by the micro- scope, or to inject them with some coloured fluid, by which their course, convolutions, and implications could be traced. The insects designed for dissection were killed by immersion in water, spirits of wine, or of turpentine, and allowed to remain in some one or other of these substances for some time, which prevented putridity, rendered the parts firmer and stronger, and the dis- sections consequently easier. When he had laid open with fine scissors the body of the insect, he carefully noted the relative situation of the parts be- fore proceeding farther ; he then extracted the viscera in a very leisurely and cautious manner, separaiting and washing away with very fine camel's-hair pencils the fat which surrounds them. After extraction he frequently floated the delicate viscera in water, and, by shaking them gently, separated the different parts from each other, and thus obtained a better oppor- tunity of examining them. In this way he was very successful in gettins: a distinct view of the air-vessels - MEMOIR OF SWAMMERDAM. 57 especially, which he could separate from all the other parts, and exhibit in a manner that excited the sur- prise and admiration of all who had an opportunity of observing them. For the purpose of cleansing thoroughly the internal parts, lie was accustomed to inject water into them by means of a small syringe, after which they were filled with air and dried ; in this way they could be preserved for examination at any future time. Not only was he thus successful in investigating the internal organs of recently killed insects, but he could examine them in specimens which had been preserved for years in balsam and spirits of various kinds. This afforded him the advantage of dissecting foreign species, many of which being of much greater size than such as occur in Europe, present all the parts in a more conspicuous manner. He could preserve the nerves in such a perfect state, that they retained their flexibility for a long time, and looked as if newly extracted from the living subject. Insects of a soft and fleshy consistency, he preserved in a variety of ways. Sometimes he punctured them in various places with a needle, and expressed all the fluids and moisture in their bodies through the pores thus made ; he then filled them with air by means of slender glass tubes, dried them in the shade, and lastly anointed them with oil of spike, in which a little resin had been dissolved, by which means they retained their proper forms for a long while. With caterpillars he devised the plan which has often been followed since, namely, making an inci- sion near the tail, and gently squeezing out all the 58 MEMOIR OF SWAMAFERDAM humours and greater part of the viscera, and then filling the empty skin with wax or some other sub- stance, so as to preserve its primitive form. The fat of insects he found to be perfectly soluble in spirits of turpentine — a discovery of the greatest importance to his enquiries, because when melted, and afterwards dried, this substance forms a coating over the viscera, completely obstructing the view of them ; but the application of the spirit effectually removes it. He often spent whole days in cleansing the fatty mat- ter from a single caterpillar, that he might obtain a clear view of its internal organization. His plan for stripping off the skin of caterpillars about to un- dergo their metamorphosis was ingenious. He allow- ed them to drop by their threads into scalding water, and suddenly withdrew them, in consequence of which the skin came off with great ease : he then immersed them in distilled vinegar and spirits of wine, mixed in equal proportions, which consolidated all the parts. He could thus remove the integuments without injury to tiie contents, and could shew the chrysalis enclosed within the caterpillar, and the butterfly within the chrysalis. He at last carried his skill to such perfection, that, according to Boer- haave, he could change the caterpillar to a chry- salis at his pleasure, and could as he pleased for- ward, stop, and regulate its motions. 59 MEMOIR OF DE GEER. SwAMMERDAMj as lias just been seen^ was chiefly employed in examining the internal anatomy of in- sects j the high reputation of the Baron De Geer, of whose life we are now to give a brief sketch, rests principally on his admirable description and de- lineation of their external structure. Deeply em- bued with a love for investigating the forms and habits of these animals, and possessing powers of observation of the first order, he succeeded in dis- covering many important facts in their economy, which he has detailed in a remarkably clear and in- teresting manner. A pupil of Linnaeus, and an ar- dent admirer of the philosophical French naturalist Reaumur, he combined the systematic regularity of the one, with the experimental skill and patient ob- servation of the other. His works accordingly have been always looked upon as a store-house of im- portant facts, lucid descriptions, and enlightened ob- servations, which have tended perhaps as much as any other publication that could be mentioned, to in- crease our knowledge of the class of animals of which they treat. Charles de Geer, Baron of Leutsta, Marshal of the Court of Sweden, Knight of the Polar Star, and Com- 60 MEMOIR OF DE GEER. mander of the Order of Vasa, was born in the year 1 720, When about four years of age^, he left Sweden, his native country, and accompanied his parents to Holland, where he continued to reside till his eigh- teenth year. His family originally belonged to that country, but had left it and established themselves in Sweden in the time of Gustavus Adolphus. The head of the family at that period was Louis de Geer, who acquired great wealth and reputation by the improve- ments he effected in manufactures and the mechani- cal arts. He introduced new methods of casting iron and brass, established founderies for canon, and manufactories of fire-arms, bringing workmen from Leige and other places to conduct them on the most approved principles, and to instruct the native ar- tists. These foreign artizans were so numerous as to form a colony in the canton of Dannemora, where their descendants long continued to reside. That the wealth and influence of this ancestor of our na- turalist were extensive, may be judged of from the fact, that, in the reign of Christinus, when the country was threatened by a foreign enemy, he equipped a considerable fleet for protecting the commerce of the coasts, exclusively from his own resources. His patriotism and philanthropy were rewarded by his name being enrolled among the nobles of the country. When in Holland young De Geer is said to have acquired a taste for Natural History by observing the proceedings of some silk-worms, which had been given him to rear as an amusement. This predilec- tion was confirmed bv his conversations with the MEMOIR OF DE GEER, 6'1 celebrated Musclienbrock, with whom he was on terms of intimacy. His studies v/ere commenced at Utrechtj but he afterwards removed to Upsal^ where he had the advantage of enjoying the combined in- structions of Linnaeus, Celsius, and Klengenstiern. Under such masters his progress in physical science was rapid ; and it was not long before opportunities occurred to afford proofs of his proficiency. By the death of an uncle, he came into possession, at an early age, of one of the largest fortunes in Sweden. The extensive iron mines of Dannemora became his property ; and he expended large sums in improving the mode of working them. Every scheme tending to promote the prosperity of his country, and the spiritual and temporal welfare of its inhab- itants, found in him a zealous and intelligent patron. Jlis wealth he liberally shared with the poor, and devoted no small part of his income to the repairing of churches, and the founding of hospitals and schools But these philanthropic objects did not divert his attention from the pursuits of science ; on the con- trary, he continued to cultivate his favourite branch of Natural History with the utmost zeal and assi- duity. As a member of the Academy of Stockholm, he regularly attended its meetings, and supplied many interesting memoirs in different departments of knowledge. His observations on insects were now beginning to accumulate, and he read a few papers on the subject to the society, which are inserted in the early volumes of their Transactions. But these observations soon became so extensive and imnort- 62 MEMOIR OF DE GEER. aut as to demand a separate work for their due de- velopment and preservation; and this accordingly he prepared to lay before the public. The first volume appeared in 1752^ under the title of Memou's pour servir a I' Histoire Naturelle des Insectes : dedicated to the Queen. It is a 4to. volume, written in French, and containing 37 plates. The principal subjects of which it treats are, the history of various kinds of caterpillars, such as leaf-rollers, those found in galls, the kinds producing butterflies and moths, &c. Many of the latter are figured and de- scribed in their perfect state. Those who have pur- chased the work, which cannot now be easily obtained, at least in this country, may have experienced how- much more difiicult it is to procure the first volume than any of the succeeding ones, without probably being aware of the cause. It is well known, that at the time of which we now speak, as well as for a long period subsequent to it, the study of the lower animals, al- though eagerly prosecuted by a few individuals in dif- ferent countries, was entirely disregarded or even held in contempt by most people, including not a few even of those who arrogated the title of men of science. Owing principally to this circumstance, the appear- ance of De Geer's first volume did not excite so much interest and attention as his own estimation of the subject of it had prepared him to expect ; and allowing, for a moment, the feeling of disappointment to get the better of his prudence, he committed a great part of the impression to the flames. But this feeling was very transient, and he resumed his labours MEMOIR OF DE GEER. 63 with as great zeal as before. A considerable period, however, elapsed (nearly nineteen years) before a second volume appeared, and four others were sub- sequently published at short intervals. It is said that he sent a copy of each of them as a present to all those who had purchased the first. The seventh and last volume was not laid before the public till after the author's death, an event which took place on 8th March 1778. He had been for many years previously afflicted with gout, and it was that disorder which terminated his useful and honourable life. The numerous and valuable objects in natural history which he had collected, were presented by his widow to the Academy of Stockholm, and the members have placed a marble bust of their benefactor in that part of their museum where they are preserved. His great work contains descriptions of upwards of 1500 species of insects, a general history of their manners and metamorphoses, and carefully executed engravings, often highly magnified, of their diflferent states, and not unfrequently of their separate parts both external and internal. These plates amount to 238, and being of a quarto size, they necessarily afford space for the representation of an immense number of objects. The contents of the first volume have been already mentioned. The second opens with an introductory sketch of insects in general ; continues the history of moths and butterflies, and includes that of bees, ephemeri, and ants.. The third is devoted to the description of Aphides, Cimices, Notonectae, grasshoppers, crickets^ dragon- flies, &c. &4< MEMOIR OF D£ GEER. The fourth and fifth are wholly occupied with the Coleoptera, and contain an account of numerous larvae pertaining to that order which were previously un- known. The sixth volume embraces the Diptera. The seventh is of a more miscellaneous description^ and besides some insects properly so called, contains a notice of crabs, spiders, scorpions, niyriapodes, and some other animals which at that period were always ranked with insects. It is from this part of his work that we have copied the beautiful portrait prefixed to the present volume ; but although a post- humous publication, it is unfortunately unaccom- panied with any account of the author's life. All naturahsts competent to form an enlightened opinion on the subject, unite in admitting that these memoirs are entitled to the very highest praise to which a work of this description can lay claim. Both" nature and fortune conspired to fit De Geer for suc- cessfully prosecuting the study to which he "^^as «;6 ardently attached. The natural endowments of his mind were of no ordinary kind, and the best educa- tion which the times could afford had the usual effect of strengthening and improving them, and adapting them to observe and discriminate with readiness and accuracy. His time was at his own disposal, and his ample fortune gave him the immediate command of every thing that could facilitate his investigations. Such a concurrence of favourable circumstances does not often happen, and it is not often, therefore, that we can expect to be favoured with w^orks of such value. They were combined, however, in the case MEMOIR OF DE GEER. 65 of a cotemporary of De Geer's, the celebrated Reau- mur ; and, as it was the works of the latter which had the greatest influence in stimulating the zeal of the Swedish naturalist for the study, it is natural to institute some comparison between them. As the result of this comparison, it may be briefly affirmed, that Reaumur shows greater skill in making his ob- servations, more felicity in planning experiments, and a readier power of exciting interest in the narra- tion of them ; but De Geer is less prolix in detailing facts, more precise, and infinitely more methodical. The absence of the latter quality in the French philo- sopher has rendered it impossible, in many instances, to determine the objects to which his observations refer. As a disciple of Linnseus, De Geer could not fail to be early impressed with the value of system, and that which he framed for the arrangement of insects claims a brief notice. In a tabular form, it will stand thus : — f 1. Lepidoptera. 2. Elinguia, (Ephemerce, Sec.) 3. Neuroptera, {Drago7i-flies, ' Gymnoptera. \ See.) 4. Hymenoptera. 5. Siphonata, {ApJddes and Cicada.) 6. Dermaptera, (^Biigs and % J Alata. ^ I Water-Bugs.) Vaginata. J 7, Hemiptera,(Coc^Toac/^es and I Grasshoppers.) ^ 8. Coleoptera. Diptera. i 9. Halterata,(Z)ijt)ferao/"Z?72?2.) ( 10. Proboscidea, {Coccus.) 66 MEMOIR OF DE GEER. Saltatoria. 11. Suctoria, (Pulex.) I ^ Aptera "^ I I Gressoria. * I ri2. Aucenaia.,(^Lepisma,Podura, Pcdiculus, &c.) 13. Atrachelia, (Spiders and Crabs.) 1 4. Crustacea, (Isopoda^ Myrio- poda.) This arrangement, wliicli has been explained in a separate work by Retzius,* is, in several respects, inferior to that of Linnaeus, the improved editions of whose Systema Naturce had previously appeared. Yet in one particular it m^s an improvement, namely by the insulation of the Orthoptera, which Linnaeus had confounded with the Hemiptera. The parts of the mouth are taken into consideration in De Geer's sys- tem, and in this respect it may be said to be inter- mediate between that of Linnaeus and Fabricius. 1\\ many instances it must be allowed to be highly natural and worthy of emanating from such a distinguished entomologist, and there can be little doubt that it would have enjoyed more consideration than has fallen to its lot, if every thing of this nature, at the time when it appeared, had not been eclipsed by the cul- minating star of Linnaeus. * Car. lib. Bar. de Geer genera et -pecies Insedorum^^c. Zvo. Lipsiasy 1783. 67 INTRODUCTION TO ENTOMOLOGY. " On reconnaitra partout rempreinte de cette Intelligexck ADORABLE, qui ciayonna, de la meme main, PHomme et la Mouche." — Bonnet, Contemp. de la Nature. Insects form a portion of that extensive department of animated nature known by the name of Articulated animals. They are so called on account of being composed of joints or segments, a structure which renders their bodies pliant, and thus compensates for one of the inconveniences that would otherwise arise from the want of a vertebral column. Some ancient authors designated them by the term annulata — quasi in annulos secta — and they are frequently de- scribed in modem works as annulose animals. They are now referred to five great classes : 1. Aniielides, such as leeches and earthworms ; 2. Crustacea, such as lobsters and crabs ; 3. Arachnides, such as spiders and scorpions; 4. Mi/riapodes, consisting of juli and scolopendrae ; 5. Insecta, containing beetles, butter- flies, &c. The term insect has likewise been suggested by the structural peculiarity just alluded to, the trans- verse divisions causing the body to appear intersected or cut into : and the Latin word insectum, from G8 INTRODUCTION TO which it is derived, is exactly synonymous with the Greek one iVTO[Ma, from which we obtain the princi- pal component part of the term Entomology.'^ Both words therefore are sufficiently descriptive of the whole articulated races, and, in fact, when originally applied, were designed to embrace them all. In the more limited and precise sense in which it is now used, the word insect is applied to such animals only as present the following characters : — no internal skeleton ; a nervous system composed of ganglions; an imperfect circulating system; respi- ration by means of tracheae communicating with the air by stigmata ; oviparous, the sexes distinct ; body covered by a coriaceous or membranous integument, and divided into three distinct sections, viz. the head, provided with two antennse ; the thorax, with six articulated legs ; and the abdomen, usually having the sexual organs at the extremity; and, finally, not presenting these parts in full developement till after having passed through (with very few exceptions,) several successive changes called metamorphoses A These negative and positive characters, derived both from external and internal parts, will be found distinctive, and completely exclusive of all the other * Scaliger affirms that the word inseda was applied to these animals, not on account of their appearance, but because they might be cut into or asunder without destroying life. Pliny adheres to the common acceptation, which is, in all probability, the right one. + Lacordaire's Introd. a VEnt. I, 3 ; Audouin's Resume d''Ei.toinologie. ENTOMOLOGY. 69 allied races v/ith which insects have any chance of being confounded. To render this the more obvious^ a . brief notice may be taken of a few of the more promi- nent peculiarities presented by each of the other arti- culated classes, when compared with that in question. The Mp'iapodes make by far the nearest approach to them in essential properties^ the internal structure being almost identical, while many of the external parts are similar : thus there are generally two com- posite eyes, two antenna?, and oral organs similar to those of masticating insects. The differences, how- ever, are sufficiently striking, and consist of the numerous segments, without any division of the body into thorax and abdomen ; in the number of feet, always exceeding six, and sometimes amounting to two hundred ; and in the body acquiring with age an increase in the number of the component segments. The Arachnides generally have the head soldered to the thorax, and many of them seem to have no other incisure than that which separates the thorax from the abdomen ; no antennae nor composite eyes ; more than six feet, and the generative organs placed, with very few exceptions, under the belly before the middle. In that section of them named Pulmon- aria, after the air has been admitted by stigmata, it is received by a kind of sacs, analogous to the lungs of vertebrate animals, and the circulation in con- sequence is pretty complete ; in the other division, * Trachiana, the respiratory organs resemble those of insects, and the circulation is therefore less perfect. The Crustacea, agreeing in very many points with 70 INTRODUCTION TO Insecta, differ from them, in regard to external parts, in Laving a greater number of legs, the head soldered to the trunk, four antennae, (in the great majority) and the composite eyes usually raised on moveable footstalks ; and, in reference to internal structure, in possessing a complete circulation, and branchiae for respiration analogous to those of fishes. The only connection which the Annelides have with the pre- ceding classes, arises from their annulated structure, the ^^'ant of an internal skeleton, a similar nervous system, and in being oviparous ; in all other respects they are widely removed from them. Their blood is red, like that of the vertebrata ; the head is scarcely distinct, and there are no antennae properly so called ; none of them possess proper feet, and the majority are hermaphrodite. Besides these distinctions, special to each indivi- dual class of the articulata, they all have this common difference from insecta, that they are destitute of wings, and do not undergo metamorphosis.* Their growth is gradual and insensible, during which many of them change their skins, but they preserve, with few exceptions, the same form they had at birth. Insects, on the contrary, pass through a variety of changes, during which they assume such dissimilar forms, that it is often impossible to recognise the same individual at different periods of its existence. The * This assertion, however, must not in one instance be made absolute, for in regard to the Crustacea, a certain kind of metamorphosis may be assumed as having been recently de- monstrated. ENTOMOLOGY. 71 different stages are four in number, tliat of egg, larva, pupa, and imago or perfect insect. All insects are, strictly speaking, oviparous. Tlie few instances which might be supposed to prove that this is not universally the case, are more apparent than real deviations from the general law. Certain two- winged flies, cocci, ground-bugs, {Cimicidce.) and aphides, give birth to larvae ; the forest-flies of the singular genus Hippobosca, and its near allies^ enter the world in the pupa state. The larvse in question, however, are not developed in a uterus by means of a placenta, like the embryos of true vivi- parous animals, but come from eggs hatched within the body of the mother ; while the forest-flies, besides being hatched in the same manner, likewise pass the penultimate stage of their life, which is probably of very short duration, in the matrix of the parent. These two tribes, therefore, may be said to -be ovo- viviparous. The eggs of insects do not often fall under our observation, on account of their small size, and being carefully concealed, by a variety of ingenious devices, that they may not fall a prey to birds and other enemies. Their most common situation, at least with such as produce herbivorous larvae, is on the leaves designed to serve these larvae as food ; at other times they are placed in fissures of wood, made by an instrument specially designed for the purpose, and not unfrequently in fruits and grain ; many are deposited in the earth, and not a few in water. They are placed either singly or in groups. Their defence 72 INTKODUCTION TO against cold and other atmospheric influences, con- sists of a coating of varnish, hair or down stripped from the body of the insect, leaves drawn carefully around them, or a covering of frothy matter. The female coccus converts her whole body into a cover- ing for her eggs, enveloping them closely on every side ; the great water-beetle {Hydrophilus piceus) deposits them in a bag, and carries them at the ex- tremity of her abdomen, like the spider commonly observed under stones, {hycosa saccata.) In form, colour, sculpture, &c., they vary infinitely in different tribes ; some of them we have already described and figured, and it will be more satisfactory to notice the peculiarities of others in connection with the par- ticular history of the insects that produce them, than to introduce here a lengthened general account of objects so dissimilar. The number of eggs laid by diflferent species, is as various as their properties. At one extremity of the scale they approach the vertebrated races, at the other they surpass all other animals in the creation. Thus a pretty large fly, which may frequently be observed resting on the stems of trees, {Mesembrina meridiana) lays only two eggs, while the female white ant lays probably not fewer than forty or fifty millions in a year, extruding them, when in the act, at the rate of sixty in a minute ! Of such as are intermediate be- tween these two extremes, the numbers are, of course, very various ; but it may be affirmed that insects are in general much less prolific than fishes. Among the latter, a million occurs occasionally, and half that ENTOMOLOGY. 73 amount may be said to be not uncommon. Aleyrodes proletella, a small hemipteron, is the only recorded insect^ except tlie white ant, that makes any approach to the last named number, and even it does not ex- ceed 200,000. An insect resembling an ant, possi- bly a Mutilla, is said to have laid 80,000 in one day. The queen bee may occasionally produce 50,000 eggs in a season, but the ordinary amount does not ex- ceed 5000 or 6000. The female wasp sometimes lays about 30,000, but commonly not more than 2000 or 3000 ; cocci between 2000 and 4000 ; some motlis a thousand or upwards ; but in far the greater num- ber of instances, even in regard to the more prolific kinds, the number may be expressed by three figures ; and, in the vast majority of cases, the eggs certainly do not amount to a hundred. Generally speaking, carnivorous species are least prolific, and herbivorous ones most so ; an ordination in harmony with the supply of food, which is limited and pre- carious in the former case, constant and almost in- exhaustible in the latter. Our acquaintance with the composition both of the exterior and interior parts of insects' eggs, is far from being complete. The integument generally offers but little resistance, being a mere membrane, not unfre- quently so transparent as to reveal the changes that take place within ; at other times it is hard, dense, and opaque. The former is the case with eggs deposited in the earth, (as takes place in many Coleoptera, Orthop- tera, and Hemiptera,) the moisture and protection of which are probably indispensable for preventing the 74 INTRODUCTION TO evaporation of the fluids ; the latter is exemplified by such as are exposed (as they often are among the Lepidoptera) to the action of the elements. No cal- carious ingredient enters into the composition of the envelope, as may be proved by the application of an acid which produces no effervescence. Under the outer envelope there is another very thin pellicle, en- closing the fluid within, the whole of which must be regarded as the yolk. The latter is a thick granul- ated mass, variable in colour, and, as far as it has been examined, found to consist of albumen, some animal glue, a yellow oil, sulphate and phosphate of natron. With the earlier stages of embryo life, we are still . imperfectly acquainted ; but when it has continued for some time, several organs can be de- tected in the process of development. Suckow first observed the intestinal canal, displaying even the constrictions which separate the oesophagus and in- testine from the stomach. Air-vessels are likewise visible, but their function is as yet dormant, as they have no communication with the atmosphere. The dorsal vessel is also developed, and Swammer- dam observed its distinct pulsations. The com- mencement of the nervous system appears in two scarcely perceptible filaments, which gradually ap- proximate, till they unite at different points forming incipient ganglia. The head, mandibles, and anal horn, (when the latter exists,) are, in general, the parts most distinctly marked in embryos. It is a very anomalous fact, that the eggs of insects often augment in bulk after they are laid, The rigidity ENTOMOLOGY. 75 of the shell renders this impossible in the generality of vertebral animals, and it is not observed to happen in other cases where there is no such obstacle, except indeed it be in fishes, which are said to present a similar peculiarity. In such instances it cannot be supposed that the eggs grow, in the proper sense of that word; they must be considered merely as increasing in volume by the distention of the flexible envelope accommodating itself to the larva, which increases somewhat in size as it assimilates the liquid filling the interior. M. P. Huber found tlie eggs of ants when ready to be hatched nearly twice the size of those newly laid. Reaumur, how- ever, seems to be of opinion that there is a positive ab- sorption from without of the surrounding fluids, and that in the case of saw-flies and gall-flies, the veget- al )le juices are imbibed from the leaves on which they are fixed, in a manner which does not easily admit of explanation. As the period of hatching depends on temperature, it varies with the state of the atmosphere, and the greater or less degree of influence with which that is permitted to act owing to the consistency of the egg- cover. The natural heat too is sometimes modified by the substances in which the eggs are placed, as when the nidus consists of dung, for example. In the heat of summer, the time that elapses between the depo- sition of the egg and exclusion of the larva is not of long duration ; but it is too variable to admit of any general period being mentioned. In perhaps the majority of cases, it varies from one to ten days; 76 INTRODUCTION TO often it extends to a month, and occasionally to several months. When the eggs of such species as have several broods in the course of the season, and are speedily hatched to admit of such frequent pro- pagation, happen to he laid in the close of autumn, they continue unchanged throughout the winter, and disclose their larvae in the spring. Notwithstanding their generally soft consistency, insects' eggs can bear great extremes of temperature without destroy- ing their vitality. There has been no deficiency in the ordinary number of insects last summer, al- though many of them would be exposed, in the egg state, to the unusual rigours of the preceding winter. Spallanzani placed some with impunity in an artificial mixture, which reduced the thermometer to 22° below zero; and experiments of the same nature have frequently been made since, with a similar result. The same skilful observer found, that a temperature of 90° did not materially injure the eggs of the silk-worm, but a higher degree des- troyed the fertility of many, and none could resist a heat of 144°. The situation selected by the parent insect, is often exposed to the highest degree of na- tural heat that can be obtained. The Melasomas of America lay their eggs in sandy places where the thermometer has been found to rise above 70° (R.) during the heat of the day, and those of Nyctelia have been observed in similar places, where it was impossible to hold the hand for a few seconds on account of the heat. Want of air is more speedily fatal to them than ENTOMOLOGY. 77 either heat or cold^ none having ever been found pro- ductive after remaining for a time in the vacuimi of an air-pump. When the whole of the fluid in the interior of the egg has been assimilated, and the young larva ma- tured, it emerges either by rupturing the envelope, gnawing it asunder, or pushing open a kind of move- able lid at the end, constructed apparently for the express purpose of facilitating its exit. Larva. Insects as often present themselves to our notice in this stage of their existence as in their perfect state, and not unfrequently attract our atten- tion by their depredations on the produce of our fields and gardens. In consequence of being so familiarly known, they are distinguished by a variety of popular names. Grubs are the larvae of coleop- tera ; maggots, mawks, and gentles, those of diptera ; and caterpillars the larvae of butterflies, moths and saw-flies : the larvae of most of the other races not differing materially in appearance from the matured insects, do not require a distinctive appellation in or- dinary language. Lepidopterous larvae, or the cater- pillars of butlerflies and moths, we have already de- scribed at considerable length * ; those of beetles also have been occasionally noticed, t and the particular history of the other kinds will be afterwards given under their respective orders and families. The pre- * See Nat. Lib. (section Entomology,) Vol. III. p. 67 ; IV. 65 ; V. 67. f See Nat. Lib. sec. Entom. Vol. II. passim. /» INTRODUCTION TO sent remarks are of a more general nature^ and ap- plicable to tlie whole. The majority of larvae have a vermlforai appear- ance^ the body being long, narrovr, and inclining to cylindric. Such as present this aspect are the kinds which differ most conspicuously from the perfect insect ; the others differ only in parts which are not influential over the general appearance. An obvious division of larvse, therefore, is into such as are wholly unlike the perfect insect, and such as bear a greater or less resemblance to it. They are all des- titute of wings, and have the common character of being unfitted to propagate the species. Some attempts have been made to classify larvae in a manner similar to that followed with perfect insects. These have not, however, been attended with much success, both on account of the inherent difficulties of the subject, and our comparatively imperfect acquaintance with insects in that condition. Mr. MacLeay was the first who endeavoured to divide them into groups, to which he assigned names suggested by the analogy which they presented to other articulated animals. Thus, for example, he names Chilogyiathiform, such larvae as offer certain analogical forms reminding us of scolopendrae ; Chilo- podiform, those resembling juli; and those resem- bhng lepisma he terms Thysanouriform. This author applied his system to the larvae of coleoptera only ; Kirby and Spence adopted the idea and extended it to the other orders ; and it has been more or less ENTOMOLOGY. 79 acted upon by other authors. But in the present state of our knowledge, a classification of this nature appears premature, there not being a sufficiency of fatrts and observations on which it can be satisfac- torily founded. The orders in which the larvae have a strong re- semblance to the perfect insect, are Hemiptera, Orthoptera, and certain genera of Neuroptera ; in all the others, with a few exceptions, thfere is no resemblance between the two states. In every instance insects may be considered as composed of thirteen segments, including the head, but in matured examples these are often merged in each other, owing to the disproportionate develop- ment of certain parts. In larvse the mode of life, movements, &c. being more uniform, an enlargement of one segment is seldom made at the expense of another, and we accordingly find the normal number distinctly marked. They are niost regular and uni- form, however, in such as bear least resemblance to the winged insects they produce, although they can be traced without difiiculty in nearly all other instances. The three segments immediately behind the head correspond respectively to the prothorax, mesothorax and metathorax of the perfect insect, and bear the three pair of legs (when these happen to exist,) which have been called the true legs, because they are persistent, to distinguish them from the abdo- minal or prologs which are caducous and peculiar to the larvae. The curious structure of the latter has 80 INTRODUCTION TO been already explained, and further details will be given hereafter. Whenever the larvae are provided with oral organs formed for suction, the same conformation obtains in the prefect insect ; but suctorial species are often produced from masticating larvae. In the former case the nature of the food scarcely varies in the whole course of the animal's existence ; in the latter it must necessarily be quite dissimilar. The various parts of the mouth, as well as other appendages of the head, are analogous in form and function to those that exist in the imago. An upper and under lip, mandibles and maxillae, and from two to six palpi can be distinguished; antennae and eyes (the latter generally of the simple construction,) are likewise present, in far the greater number of cases. The mandibles vary in form and consistency according to the nature of the substances upon which they are designed to act : in many carnivorous tribes they are long and curved ; and in Dytiscus, Hemerobius and Myrmelion, they have another and a singular function superadded to their ordinary uses : they are perforated throughout their whole length, and thus form a tube through which the animal sucks the juices of the prey which it has secured by thdr means. Among many Diptera, the mandibles serve as instruments of motion ; the larva fixing its poste- rior part to the plane of position, and then stretching its body in advance, seizes some point of support with its jaws, and by their aid easily drags the body ENTOMOLOGY. 81 forwards. Maxillae are sometimes wanting, (as among many dipterous larvee,) but when present they are placed immediately under the upper jaws, and are more or less subservient to mastication. They are generally without the lobes which distinguish the corresponding parts of the imago, but there is, for the most part, a palpiform process, analogous to the in- ternal maxillary palpus, or what is called galea in the orthoptera. Palpi exist in all larvae save dipterous and hymenopterous ones, but they are often short and inconspicuous. The maxillary palpi are some- times four in number, at other times only one is at- tached to each maxilla ; the labial palpi are always limited to two. Their shapes are conical, setaceous or filiform ; the joints variable in number, and not unfrequently branched. The upper lip presents nothing peculiar, but the under lip, in the tribe of dragon-flies, (Libellulidaej) assumes a very singular form, as will be seen when we come to specify the peculiarities of the order Neuroptera. In connection with the under lip, there is an instrument peculiar to some larvae, namely, a spinneret — a small conical tube through which the silken threads are drawn, which are so indispensable to the economy of a large pro- portion of them. The antennae are far from presenting that variety of design and beauty of structure which render them, not unfrequently, very ornamental ap- pendages to insects in a state of maturity. They are often entirely wanting, (as in the maggots of many two-winged flies, bees, &c.) and frequently so minute, that even when they do exist, they cannot easily be F 82 INTRODUCTION TO detected. Not rarely, however, they are pretty con- spicuous, consisting of four or -five joints in the ma- jority of beetles, and of two or three in caterpillars. The joints are frequently contractile within each other, so that the antennae can be protruded or with- drawn at the pleasure of the animal. The head of larvae is usually of a harder substance than the rest of the body, and in that case is com- monly of a triangular or orbicular shape; but its covering among the diptera is soft and membranous, from which results the singular anomaly that it is capable of dilatation and contraction, and therefore of assuming any form the insect may desire. The remarkable spines that arm the heads of many foreign caterpillars, have been already mentioned.* On the various and numerous appendages of larvae, whether serving for respiration, ornament, or defence, it is unnecessary to enlarge in this place, as it would only be anticipating what can. be more appropriately introduced hereafter. Their anatomy will be con- sidered conjointly with that of the perfect insects. But there are other interesting features in their history, to which it will be most convenient to advert in this place, namely, their growth, moulting, and prepara- tions for entering upon the pupal or penultimate state. The growth of larvae is in most cases rapid. The whole structure of the animal, indeed, indicates pro- vision for its speedy increase in size. The instru- • See Nat. Lib. Sec. Ent. vol. v. p. 67. ENTOMOLOGY. 83 meiits of munducatlon are strong and efficient ; the digestive organs greatly developedj and the skin perio- dically thrown off to remove any impediment to the distention of the body. The consumption of food is necessarily greats, in some cases exceeding that of any other animals, regard being had to their respec- tive size. In fact, many of the kinds which consume the foliage of plants eat with little intermission ; and, in some instances, they continue to feed both by night and day. The growth of the larvee of flesh-flies (^Sarcophagd) is unusually rapid, some of them having been found to become 200 times heavier in twenty- four hours. When it has attained its full growth, the caterpillar of the goat moth is sometimes 72,000 times heavier than when newly hatched. The ex- periments of Count Dandalo on the silk-worm, make it appear that when just hatched, this caterpillar is a line in length, and a hundred weigh about a grain ; after the first moulting, the length of each is four lines, and a hundred weigh fifteen grains ; after second moulting, length 6 lines, weight 94 grains ; after third moulting, length 12, weight 400 ; after fourth moult- ing, length 20, weight 1628,* after fifth moulting, the length of each is upwards of three inches, and a hundred weigh about 9500 grains. The number of these moultings or changes of skin varies greatly in different insects, but it is always alike in the same species. The intervening periods like- wise vary, being dependent on the length of life allotted to the larvae. In the silk worm, as has just been seen, the moultings are five, and all these occur 84 INTRODUCTION TO within the space of thirty days. From five they extend to nine or ten^ the latter number having been observed in the tiger moth, {^Chelonia caja.^ But the great majority of insects do not undergo this ope- ration oftener than three or four times. The cater- pillars of butterflies are usually limited to the for- mer of these numbers, those of moths to the latter, but among moths many other exceptions occur besides the one mentioned above. The proximate cause, as already intimated, of this moulting, is the more rapid expansion of the body than of the skin, which, in consequence, soon exceeds the capa- city of its envelope : the latter, it is true, admits of a certain degree of distention, but a few fixed points on its surface, as well as the rigidity of the part enclosing the head necessary to give support to the masticating organs, prevent it keeping pace with the growth of the body. The larva ceases to eat when the change is approaching, and, during this temporary suspension of its ordinary employment, the fat lying immediately beneath the outer skin is absorbed, a circumstance which greatly hastens the crisis by abstracting the moisture from the skin and shrivelling it, while, at the same time, it tends still further to dilate the internal parts. The colours, being dependent in a great measure on the fresh- ness and moisture of the skin, also become dull and confused. The only motions made by the larvae are occasional contortions and undulatory movements of the segments, which ultimately produce a complete separation between the exterior skin and the new ENTOMOLOGY. 85 one beneatli it. By continuing these^ a rent is soon made, usually on the back behind the head, through which the creature forces its way, while the exuviae are held back by the hinder extremity, which the larva was careful previously to attach to some object with this very design. The divestment is so complete and adroitly managed that the cast integument may easily be mistaken for a living larva, as it exhibits all the parts which characterised it, apparently without having undergone any material change. This process of renovation, however, is not wholly confined to the external parts ; several of the viscera also are said to cast a fine skin, and even the aeriferous tubes, though so numerous and delicate, undergo the same process, and the rejected membranes are gradually expelled from the body through the stigmata. Several tribes of larvae do not change their skin at all, not even when about to become pupae. These belong chiefly to the order Diptera, whose membran- ous contractile heads and expansible skin removes the necessity of subjecting them to the same law as those diflferently circumstanced in these respects. The last change of skin, which occurs just before the assumption of the pupa state, is essentially similar to the others, but it is preceded, in many instances, by certain precautions and preparations, with a view to security and comfort during the quiescent condition about to ensue. The larva leaves its wonted haunts, and seeks some reti'eat where it will be less exposed to the weather and its numerous living enemies ; the crevices of trees and walls, the shelter of dead leaves. 86 INTRODUCTION TO moss, or stones, the eaves of out-houses, and similar places, are industriously sought after, and many bury themselves a considerable depth in the earth. But the selection of a suitable retreat is far from being their only care, at least with a great many ; other precautions are resorted to, many of which afford examples of singular ingenuity and persevering labour. This is particularly the case with the caterpillars of butterflies and moths. The former either suspend their chrysalides horizontally by the tail and a silken band round the middle, or by the tail alone, allowing the body to hang perpendicularly. The manoeuvres by which the caterpillar manages to place the band round its body are extremely curious and interesting, and have, therefore, been particularly described in the volume of this series already mentioned and to which we must again refer. The cocoons of moths have likewise been described in a similar volume de- voted to their history ; and that tribe of insects af- fords the best examples of this species of fabrication. Most of the Hymenoptera likewise form silken cocoons ; a few Coleopterous and Dipterous genera, (Hypera, Donacia, Mycetophila,) and the Neurop- terous groups Hemerobius and Myrmeleon ; the latter differing from nearly all the rest in having the ap- paratus for spinning their threads at the extremity of the abdomen, instead of in the head. Cocoons of silk are often strengthened by the addition of other materials, such as particles of earth, portions of leaves, fragments of wood, &c. ; and occasionally cocoons are formed altogether of these substances held together by ENTOMOLOGY. 87 a glutinous secretion without the assistance of threads. Saw-flies, and some other Hyraenopterous tribes, construct a double cocoon, the outer one not united to the interior, biit inclosing it as the shell of a nut does its kernel. Many larvae dwell in habitations which they form with much skill and labour, to de- fend their tender bodies, and these likewise serve as a ready and efficient protection for the pupa. Such are the cases of the May-flies {Phri/ganece) which are common in slow flowing streams, and curious on account of the materials with which they are covered ; the mantles of many leaf-rolling caterpillars, and the portable tents constructed by others. Dipterous larvae are frequently converted into pupae within their own skin, which changes its form and becomes of a more rigid texture for the purpose of affording it more effectual protection. The change to a pupa does not always take place immediately after the preliminary arrangements are completed, although the contrary is the general rule ; a period of inactivity often ensues ; and some caterpillars remain unaltered within their cocoons for months together. Pupa. This is the most general term applied to insects in the third stage of their existence, that, namely, which intervenes between the larva and imago. It was suggested by their appearance, which resembles that of a child wrapped up in swaddling clothes, all the parts being closely folded down, and enclosed in a general envelope. It is, therefore, very applicable to the majority of them, as they are com- pletely dormant and inert, incapable either of moving 88 INTRODUCTION TO or of taking food. But although this is the general condition of pupa, it is by no means universally so ; many scarcely differ in appearance from their larvae, and are equally capable of moving about, and equally voracious. This aifords a convenient means of sepa- rating them into two great divisions, the one compre- hending such as resemble their larvae, the other those which bear no resemblance to their larvae. To the first of these divisions belong all those pupae which Linnaeus called complete, viz. the Orthoptera, Hem- iptera, (with some exceptions,) and certain tribes among the Neuroptera. The principal perceptible difference between these pupae and the perfect in- sects consists in the wings not behig fully deve- loped ; but these organs approach gradually to a state of greater maturity with the age of the pupa, although without breaking through the case that con- tains them. The general form of the body, and the organization of the mouth, are similar in both states, the other differences besides the one indicated, when such exist, being confined to the legs or certain other parts of structure which are of utility to the pupa when it differs in its economy, as sometimes happens, from the imago. Thus the pupa of Cicada has the forelegs greatly thickened and adapted for digging, because in that stage of its life it lives be- neath the ground ; after undergoing its* final change, it frequents trees, and the fossorial legs, being no longer useful, disappear. The respective states of larvae and pupa in the tribes in question being not indicated by any marked character, it is often ENTOMOLOGY. 89 very difficult to say at what precise point of time the transition from the one to the other takes place ; and in such species as are perfectly apterous, (such as Cimex Lectularius and many Phasmidae,) a like difficulty may he experienced in distinguishing the pupa from the imago. The second division comprises the pupae of all the orders not enumerated ahove, and constitutes, there- fore, by far the most extensive of the two. Although they agree in the general property of being wholly unlike the larvae, and in being incapable of eating and walking, they yet offer not unimportant distinctions among themselves in several particulars. Some have all the limbs encased in separate membranous en- velopes, and therefore lie free, although closely ad- pressed to the body ; others are covered with a hard skin or horny case, on which the different parts can be traced by their forming projecting lines ; while in others the integument is opaque and uniform, con- cealing every thing within it. To the first of these belong the entire orders Coleoptera and Hymenoptera, as well as certain tribes among the Neuroptera and Diptera. These were called by Linnaeus incomplete pupae, by Lamark mumice coarctatcBy and by Bur- meister pupce exaratce. The second form the obtected pupae of Linnaeus {pupce larvatce, Burm.^ and com- prehend all those of the order Lepidoptera, which are usually known by the term chrysalis. The third sub- division includes the larger proportion of the order Diptera, which were the pupce coardatce of Linn., the case being nothing more than the dried skin of 90 INTRODUCTION TO the larvae. The following figures afford examples of these different kinds of pupse^ the numerals referring to the order in which they have just been named. On examining the interior of a pupa immediately or shortly after it is formed, it is found to consist al- most entirely of a milky fluid, which soon, however, acquires the consistency of pulp, when the members of the future insect can be detected. They are not long in enlarging by the absorption of the ambient matter, and when they acquire their full size, they completely fill, in most instances, the interior of the pupa-case. The integument, as above intimated, varies greatly in its consistency. In the Lepidoptera it acquires its rigidity from a viscous fluid, which oozes out from the region of the thorax, and spreads over the whole surface, forming a hard and varnished shell. The superficies is for the most part naked. In some cases, however, it is tufted with hairs, (as in Orgyia pudihunda, Leucoma Salicis;) occasionally ENTOMOLOGY. 91 it bears insulated spines; and not unfrequently it is tubercular. The colour of the kinds that are little exposed, from their situation, to the action of light, is generally yellowish -white ; many of those, however, which are concealed beneath the earth, are light-bro\vn ; most of those belonging to the Lep- idoptera are greenish or brown, sometimes speckled, and occasionally ornamented with golden spots, on which account they were first called Chrysalides and Aurelise. Many pupae have strong angular points projecting from various parts of their bodies, and sometimes these are processes designed for a par- ticular function. Such, for example, are the clavate appendages which project from the sides of the thorax in the pupae of gnats, and some other dipter- ous species which live in the water. The dorsal segments of many are armed with sharp serratures looking towards the anus, which serve an important purpose in their economy, for it is by their means the pupa works its way to the surface of the ground, when the perfect insect is about to be disclosed. When the segments are curved, the convex side, by means of these spines (called adminicula by Kirby), finds a point d' appui higher up than it occupied formerly, and when it has attained this elevation, another curvature of the abdomen enables it to gain another step. In this way they have no diffi- culty in rising to the surface merely by wriggling the abdomen from side to side. This structure is well exemplified in the large pupa of the goat moth, a highly magnified view of whose serrated dorsal ridges 92 INTRODUCTION TO presents the appearance delineated in the adjoining wood -cut. The pupa having made so much nearer an ap- proach to the perfect form than the larva, exhibits some indication of the principal divisions of the body which afterwards become so strongly marked. A slight constriction frequently points out the bound- aries of the head, thorax, and abdomen. Regarding the exterior sheath as the case {^theca) of the pupa, Kirby and Spence have assigned a nomenclature to its principal parts : the anterior division enclosing the head, is called the Head-case {cephalo-theca) ; next to this is the Trunk-case {cyto-theca) ; and lastly the Abdomen-case {gastro-theca). The coverings of all the other parts receive names from the Greek words for these parts compounded with theca; thus the ENTOMOLOGY. 93 eye-case is called Oplithalmotlieca, the antennse-cascs, Cerathecte, &c. The length of time insects pass in this stage of their existence varies from a few days to nearly two years. Each species^ however^ has in general a de- finite period assigned it from which there is no mate- rial deviation, unless under very peculiar circumstances. Perhaps the most general duration is from two to four weeks, hut, even in the same species, this depends upon the season of the year, for a pupa which would disclose the perfect insect in a few weeks during the summer, will frequently lie dormant throughout the entire winter. Unless a provision of this kind ohtained, it is obvious that many insects would in- fallibly perish from being brought into existence at a time when it is impossible to find the means of maintaining life. The immediate cause of this pro- longation of their quiescent condition is to be found in the effects of the winter's cold, the more remote one in the wise ordination of providence. Artificial heat, as has been already stated in a former volume, will mature the perfect insect and make it burst from its prison at any period of the year; and, in like manner, artificial cold will retard its birth. From these considerations, it is obvious that the evolution of the imago depends on the evaporation and assimi- lation of the fluids, and this takes place in a more speedy or tardy manner, according to the greater or less degree of heat to which the pupa is exposed ; it does not, however, happen that pupse of the same species, placed in precisely the same circumstances* 94 INTRODUCTION TO always produce the imago at the same time; a difference of many months, even of years, has been observed in certain instances, an anomaly which we have hitherto found no means of explaining, although it is not difficult to perceive that it may often tend to the benefit and even the preservation of the species. The manner in which butterflies and moths make their escape from their pupa-case, when about to become denizens of the air, has been already ex- plained,* and it only remains for us to say a few words respecting the mode in which this operation is accomplished among other tribes. The incomplete pupse have a comparatively easy task to perform, as their limbs are each in a separate envelope, and when one is free it can assist in the extrication of the others. But the coarctate pupse are enclosed in a common case, the texture of which is more than usually rigid and unyielding; unless, therefore, a special provision had been made for their liberation, their condition would have been nearly hopeless. This provision consists for the most part of a circular suture near the anterior end, where the head lies, which so weakens the adhesion of the end to the body of the puparium, that it can be pushed open from within like a kind of lid, and afford sufficient room for the inmate to escape ; this lid, in some instances, consists of two semicircular pieces, which open like a pair of folding doors. Reaumur has made us acquainted with the singular fact that some kinds * See volume of Nat. Lib. formerly referred to. ENTOMOLOGY. 95 of Dipterous insects have the power of introducing air into their pupa-case for the purpose of forcing a passage out of it. The air is said to he introduced under the middle part of the head, which becomes inflated into a membranous vesicle, and thus acts upon the end or lid of the pupa-case, and, in time, forces it open. This singular lever is necessary in the case of the flies alluded to, in consequence of the substance of the puparium being so hard as to ofier more than usual resistance. Many subterraneous pupse assume the perfect form beneath the ground, and others make their way to the surface before undergoing that change. In the former case, the insect remains where it was disclosed till it acquires sufficient strength and hardness to render it safe to force a passage upwards ; the rose- chafer (^Cetonia aurata,^ continues about fifteen days, the cockchafer {Melolontka vulgaris,) and Oryctes nasicornis, nearly a month. This, however, would obviously be impracticable for soft winged insects, (such as moths, two-winged flies, &c.) and it is, therefore, necessary that they should reach the sur- face (whether it be of the ground or the rotten trunk of a tree,) while yet pupae. We have mentioned the means by which the pupa of the goat-moth effects this, and a similar plan is followed by most others so circumstanced. Such pupae as are enclosed in co- coons are provided with means for forcing a passage through this additional obstacle of which an account has been given when treating of the insects by which cocoons are usually" constructed. Other peculiarities 96 INTRODUCTION TO exhibited by pupae previous to the disclosure of the perfect insect will be afterwards given in the particu- lar history of the Orders^, to which we therefore refer. Imago or Peifect insect. When an insect quits its pupariumj it is said to be complete or perfect^ be- cause it has then gone through all its changes, has all its parts fully matured and developed, and is capable of executing all the functions peculiar to its nature. The sexual distinctions, in particular, are now mani- fested, and the species become capable of continuing their kind. The wings are unfolded, and by their means they may almost be said to become inhabitants of a new element. It is now, in short, that, consi- dered collectively, they exhibit in an especial man- ner all that diversity of form, peculiarity of structure, beauty and variety of colouring and ornament, as well as those singular instincts and modes of life for which the class is so remarkable. In considering the perfect insect in this place, we propose to give a view of its external and internal structure — in other words, of the exterior crust and organs as they appear to the eye, and of the internal parts as ascertained by dissection, or the anatomy properly so called. In so doing, we must necessarily render our account as general as possible, reserving the details of the modifications which the various parts undergo, till we come to treat of the separate orders ; for it is, in fact, by these modifications that the various orders are constituted, and a review must, therefore, be taken of all the^most important parts of struc- ture as introductory to each, before it can be fully ENTOMOLOGY. 97 understood in what its peculiar characters and attri- butes consist. The external integument, or crust of insects, oc- cupies the place of the skin in higher animals, as it forms a general envelope for all the parts ; but, unlike the skin, it is of a rigid and horny consistency. In the latter particular it is liable to a good deal of varia- tion, being sometimes horny and inflexible, (as in beetles,) at other times comparatively soft, and yield- ing to the slightest pressure. In all cases, however, it has sufficient strength to give effectual support to the muscles, which are attached to its interior surface, thus serving the same purpose as the bones of the vertebrata ; on this account, insects have been some- times described as bearing their skeleton externally. Besides resembling the true skin in its situation, it is found to display further conformity to it, in con- sisting of three principal layers, viz. the epidermis or exterior layer, the rete mucosum, and lastly, the leathery tunic, sometimes called the dermis or corium. The first of these is smooth, shining, and generally uncoloured, for the most part thickly perforated with small holes, through which the hairs rise to the sur- face. The mucous tissue {rete mucosum) consists, according to Strauss, of two layers, the upper of which is closely attached to the epidermis, and in this reside the brilliant colours with which so many insects are adorned.* The third layer is vrithout colour, and * Except, of course, the Lepidoptera, in which the colours, as is well known, are produced by a superficial covering of G 98 INTRODUCTION TO consists of various strata of complicated fibres, which admit of being separated from each other. It is from this skin that the hairs originate, and from which they derive their nourishment. In regard to chemical composition, the external covering approaches to the nature of horn, but it differs from that substance by the admixture of a peculiar substance, viz. chitine or entomoline. Por- tions of phosphate of lime and magnesia are also constituent ingredients, although they exist in small quantities. One of the peculiar properties of chitine is its insolubility in potass. " Exhibited separately, which is very easy, by means of steeping horny parts in a solution of potass, it appears as an almost colour- less transparent substance, which becomes brown in nitric acid, and in the dry distillation produces no carbonate of ammonia, and therefore appears to contain no azote ; it burns without previously melting, but is soluble in boiling or heated sulphuric acid. " Besides the above, small portions of albumen, a peculiar brown colouring matter, which dissolves in caustic potass, but not in boiling alcohol, as well as traces of phosphate of iron, have been found in the horny integument of insects, upon different analyses. The albumen belongs doubtlessly to the third tunic, as does the brown colouring matter to the mucous rete : to this, also, we attribute the chitine, where- by the true horny skin, namely, the epidermis, will scales : yet even these scales, according to Cuvier, obtain their colour from being, in the chrysalis, in a state of mucosity, similar to that which is found under the skin of the caterpillar. ENTOMOLOGY. 99 be found to agree entirely with the horns of the higher animals." * The integument is more or less obviously divided in a vertical direction into thirteen segments^ and each of these segments has been supposed to consist of four parts intimately united, which would make the whole case consist of fifty two pieces.t But the three most obvious divisions, manifest to the most cursory observation, are the head, thorax and abdomen. The Head is very variable in shape^ but most com- monly spherical, either the longitudinal or transverse diameter predominating. It forms a kind of box, having an aperture before and behind : the former is occupied by the organs of the mouth, the latter by the muscles, &c., which connect the head with the thorax. The whole of the lateral superficies is oc- cupied by the eyes. Particular regions of it have re- ceived names from the analogy which they are thought to bear to the parts of the head in the higher animals, but scarcely two authors agree in their nomencla- ture and definitions. Considered as a whole, the cephalic box may be regarded as the skull, {craniurn) since it encloses what is regarded as corresponding to the brain of the vertebrata. The upper portion of the skull extending from the region of the eyes * Burmeister Manual of Entom. \ Shuckard's Trans, p. 231. -|- " In many of these," says Mr. Ne^vman, " each segment very evidently consists of a dorsal, a ventral, and two lateral plates or bones, which would produce the number two hun- dred and eight." Ent, Mag. i, 398, 100 INTRODUCTION TO backwards, is the Epicranium, the posterior portion of whichj where the stemmata are often situated, is the Vertex. Bounding the epicranium in front and extending to the clypeus, is a space which has been called the forehead, {frons). The clypeus (nasus of Kirby, Epistome of Latreille,) occupies the ante- rior part of the head immediately above the mouth, it being apparently its office to guard the oral organs from injury. Sometimes the whole of the anterior portion of the head from the mouth to the region of the eyes, is denominated the face, {fades) and in certain tribes particular parts become developed, and consequently require to be indicated by addi- tional names, which will be afterwards noticed. On the lower and lateral regions of the head, the fol- lowing parts may be particularized : the Gula or throat, which lies immediately posterior to the under lip, and extends to the point where the head joins the prothorax: the cheeks, {gence) composing the sides of the head from the eyes downwards to the mouth j the posterior portion of which lying in the vicinity of the eyes, is termed the temples, {tempora.) When the head is vertical or nearly so, the back part of it is called the occiput.* Such are the principal fixed parts of the cranium, if we add the eyes and ocelli ; when others require to be definitely pointed out, they may in general be intelligibly named and characterised from their pro- pinquity to other parts. We are now to notice the * For delineations of the different parts of the head, thorax;. &c. see Plate 1st, with the annexed explanation. ENTOMOLOGY. 101 moveable parts, namely^ the antennae and the organs of the mouth. The former are the conspicuous and well known jomted organs, placed one upon each side of the head between the angle of the mouth and the eyes. They are never wholly absent, and never exceed or fall short of the number mentioned. They are planted in a cavity or socket, (Toruhis) and the base is usually subglobose, forming the pivot upon which the antenna turns. Each of the joints of which they are composed has a separate motion, and they are therefore susceptible of every flexure the insect may require to give them. In regard to situation, general form and construction, number of joints, clothing, &c., antennae vary greatly in different tribes, and their peculiarities in these respects will be specified when treating of these tribes separately. The mouth of insects differs in its external appear- ance according as it is designed to act upon solid or liquid food ; in other words, according as it belongs to a masticating or suctorial species. But although so dissimilar in external aspect, the component parts are essentially the same in both. In masticating insects, (mandibulata) the parts are free and highly developed; in suctorial species, (haustellata) they are more or less united, forming a kind of tube for the transmission of fluids. Although we have already described both these modifications of form, some re- capitulation may be useful in this place, both for the purpose of presenting a continuous view of insect structure, and conveying as accurate a notion as possible of parts so essential, whether viewed in re- 102 INTRODUCTION TO lation to the insect's economy, or the uses that have been made of them by naturalists in their systematic arrangements of the class. When a mouth organised for mastication is viewed from above, the first part that meets the eye is the labrum or upper lip. It is a corneous plate, of very variable form, united posteriorly by a mem- branous hinge to the clypeus, with which many authors, and among others Fabricius, have con- founded it. It covers the mouth above, and assists in retaining the food while undergoing the pro- cess of mastication by the mandibles. The last named organs, otherv/ise called the upper-jaws, are two strong, triangular, wedge-shaped, or elongated pieces, placed immediately below the labrum, arti- culating with the head by means of apophyses or processes, and moving horizontally in opposition to each other like the blades of scissors. When of a horny substance, which is usually the case, they are commonly dentate on their inner edge, but the den- ticulations are seldom or never alike in both blades, but so arranged that the projections of the one enter the notches of the other, thus admitting of a close union. The maxillce, or feeler-jaws, as they ha\^ not inappropriately been called, are placed below the mandibles, and correspond to them in being two tri- angular hooks, moving horizontally in opposition to each other. They are always smaller than the man- dibles, usually of a more delicate texture, and instead of being toothed on their internal edge, are- for the most part fringed with hairs or bristles. They may ENTOMOLOGY, 10^ be regarded as divisible into four parts : the insertion or hinge, (cardo) which is the lowest portion by which it articulates with the throat, and which is usually placed nearly at right angles with the follow- ing part. The latter is the stalk, {stipes) generally pretty strong and thick, at least in its upper part, although frequently it is soft and membranous beneath. Attached to this, on its outer side, is a small portion which has been named the feeler-bearer {squame palpi/ere of Strauss,) hecause the maxillary palpus is always inserted on its outer edge. The terminal portion of the maxilla, which usually ap- pears in the shape of a hook,* ciliated on its inner edge, and frequently toothed at its extremity, is the maxillary lobe, (internal lobe of Latreille, lacinia of Macleay.) This, which is an important part, as it acts immediately upon the food, is very often simple, but at other times it is divided into two pieces, in which case the one is called the external, the other the internal lobe of the maxilla. The external lobe is sometimes called the galea or helmet, (this is its appropriate name among the Orthoptera) but when it is jointed and palpiform, as it frequently is among the carnivorous Coleoptera, it is commonly described as the internal maxillary palpus. The maxillary pal- pus properly so called, is a pretty long, jointed, com- monly filiform process, the presence of which always distinguishes the maxillae from the mandibles. The * The lobe of the maxillae is occasionally terminated by a moveable claw, as may be seen in certain Orthoptera and the tribe of Cicindelidae or tiger-beetles. 104. INTRODUCTION TO figure and proportion of the joints are very variable ; the terminal joint especially exhibits a great variety of forms, which are of great service in distinguishing genera. The number of joints never exceeds six. Closing the mouth on the underside is a piece which acts as an antagonist to the upper lip, and has therefore been named the under lip or labium. The basal portion of this constitutes the mentum or chin ; which is a quadrangular, trapezoidal or semi- circular plate. The part immediately adjoining this and anterior to it, is the labium properly so called, usually bearing the labial palpi. The terminal por- tion is the ligula or limb, frequently divided into lobes. The labial palpi are similar in structure to the max- illary pair, but they always consist of a smaller number of joints, the greatest amount never exceed- ing four. The tongue {lingua) is usually a very obscure member of the trophi, and authors do not always assign that name to the same organ. It may be described as the lining membrane of the under lip, the anterior angles of which sometimes protrude in front, as may be seen among the Carahidce, a tribe in which the projecting points have been named paraglossae. It is most distinct among the orthoptera. On examining a mouth formed for suction, it ap- pears, at first sight, to be constructed on such a dif- ferent model from that just described, that it seems almost a hopeless case to attempt to trace any analogy between the parts. But it is not long before we can discover an essential agreement, although the ENTOMOLOGY. 105 various organs are, of course, greatly modified, some being more fully developed, and others becoming almost or vi'holly obsolete. Three principal types of form in the construction of the mouth prevail among haustellate insects, which have received the names of Promuscis, Proboscis, and Haustellum. Each of these is characteristic of a particular order, and will therefore demand a detailed examination in the sub- sequent exposition of the peculiar characters of these orders j at present it may be merely remarked, that the tube for the transmission of the fluids is generally formed by the elongation of the maxillse^ accompanied with some accessory parts, sometimes the upper, at other times the under lip forming a lengthened sheath to support and protect the other parts. The next primary division of an insect which re- quires attention is that which may be described gene- rally as lying between the head and abdomen, viz. the Thorax. It is a highly important part, in as much as it bears all the organs of motion, and determines in some degree the whole shape of the insect ; the variety of its forms and the multitude of pieces en- tering into its composition, render the study of it rather difficult, and this difficulty has been increased by the complex nomenclature which has been assigned to its parts. A slight inspection suffices, for the most part, to shew that it is made up of three principal parts ; the anterior of these, bearing the fore-legs, is termed the prothorax ; the next, which supports the middle-legs and the fore- wings, (in such species as are provided with four wings,) is the mesothorax; 106 INTRODUCTION TO and the hinder section, to which tlie hind-legs and hind-wings are attached, is the metathorax. In ap- terous insects these divisions are the only ones dis- tinctly determined, but in those provided with wings a more complex arrangement results from the mus- cular apparatus requisite to produce their movements. In its greatest state of development, (which it attains among the coleoptera and orthoptera,) the prothorax (Manitrunk of Kirby,) forms that large, quadrate, rounded, or oblong piece intermediate be- tween the head anrl abdomen, which, in popular and descriptive language, is simply called the thorax. Its surface is the pronotum of Burmeister, the thoracic shield of Kirby. Its forms are too diversified to be specified here ; it commonly has an impressed line down the centre, at other times the centre rises into a longitudinal serrated ridge. The in- ferior plate is named \he prosternum by Burmeister: {Antepectiis, Kirby,) it is of more limited dimen- sions than the surface plate, and usually projects into a kind of anijle beneath : the anterior less are inserted, one on each side, towards the middle, and the prothoracic spiracle is commonly a little behind them. Viewed from above, the prothorax sometimes forms merely a narrow ring like a collar, and in certain tribes all traces of it disappear in the dorsal aspect, the head being apparently articulated directly with the mesothorax. The various changes of form which the prothorax, as well as the other primary divisions, undergoes in the different orders, together with its appendages, and the degree of development ENTOMOLOGY. 107 observable in particular parts, will be afterwards traced as these orders pass successively under our review. The mesothorax is not always readily recognised by its situation as intermediate between the prothorax and metathorax, for, as above intimated, it frequently appears in direct connection with the head ; but it may always be known by supporting the fore-wings and middle pair of legs ; its anterior part is sometimes received into a cavity of the prothorax, when the latter is highly developed superiorly, at other times the union between the two is by the edges. So intimately is it soldered behind to the metathorax, that there is frequently no visible suture, but in many instances traces of the union can be detected. Ac- cording to Burmeister, (whose nomenclature of the parts in question appears to us preferable to that of most authors, on account of its greater uniformity and simplicity,) this section consists of seven pieces, but, as three pairs of these are so closely united that each pair seems to form only one piece, it may be regarded as composed of four principal parts; the first of these, the mesonotum, (corresponding to the dorsolum and scutellum of Kirby and Spence,) forms the dorsal covering of the mesothorax. In many insects it is almost invariably concealed, but in others it is 'exposed and conspicuous ; in such cases its form is usually square, and there is a superficial indication of its consisting of two parts ; the one of these, the true back, exactly corresponds to the dorsolum of Kirby, the other is the scutellum, which 108 INTRODUCTION TO appears as a triangular piece interposed between the wings at their base; it is very conspicuous in most beetles, and, in the heteropterous section of the hemiptera, it is sometimes so large (as in Tetp-a, Fab.) as to cover the whole abdomen, having both the liemelytra and the wings beneath it. In certain cases there is no indication of the scutellum on the surface, in consequence of it being covered by the elytra and pronotum, but it is always present, al- though the insects in question (Copris may be given as an example,) have been called exscutellati, or des- titute of a scutellum. A strong membrane or process may be frequently observed connecting the scutellum with the elytra or upper wings, and acting as a kind of counter-check to the latter during flight. This is best seen in the great lanthom-fly, {Fulgora lanternaria,) where there is a flat plate on each side of the scutellum, with a ridge or nervure running along it to the base of the tegmina, which nervure consists of a number of cartilaginous rings, and thereby admits of tension and relaxation, as the tegmina rise and fall. The part in question has been named ihefrenum or bridle. The scapulae constitute the second principal por- tion of the mesothorax. They lie close upon the me- Bonotum, one on each side in front, assisting to form the articulating socket of the superior wings; they then contract themselves, in order to pass into the cavities of the prothorax, and, with their opposite wing, they pass down the sides of the second thoracic segment. They admit, therefore, of being regarded ENTOMOLOGY. 109 as of two divisionSj which may be distinguished as the anterior and posterior wings of the scapulae.* The spiracle of the mesothoracic segment^ which had been long overlooked, owing to its latent posi- tion, is found beneath and a little beyond the poste- rior wings. The patagia and teguloe of the Lepidop- tera and Hymenoptera, (which we shall afterwards allude to, when considering these orders) are attached, the latter to the mesonotum, the former to the poste- rior wing of the scapula. The 7nesosternum forms the under side of the mesothoracic case, being directly opposite to the mesonotum. It is in all cases distinct, and some- times comprehends a considerable area, in which the sockets of the middle legs are included. The only primary segment of the thorax remaining to be considered, is the Metathorax which, like that last described, supports a pair of legs and a pair of wings. It does not attain a high degree of develop- ment in any of the orders, except among the Coleop- tera and Orthoptera ; its structure, consequently, can be most satisfactorily investigated in these. It may likewise be regarded, according to the authority we have chiefly followed in describing the constituent parts of the thorax, as consisting of seven pieces, which bear considerable resemblance to those of the mesothorax. The dorsal portion is the metanotum, commonly quadrangular, with the front emarginate, and the anterior angles consequently advanced. The * Purmeister's Manual, p. 91. 1 1 INTRODUCTION TO scutellum sometimes extends over the anterior edge of the metathorax ; in some instances it entirely con- ceals its surface. An impressed line sometimes sepa- rates an anterior portion from the rest, and in such a case this is called the Postscutellum. As the internal cavity of the mesothorax is separated from that of the metathorax, by a partition denominated the Mesopkragmaf so the latter is separated from the abdomen by a similar parietal wall, called the Meta- phragma, a small space only being left for the passage of the necessary organs. The ventral plate of the metathorax is the meiasternum, a portion which most commonly assumes a shape similar to that of its counterpart above, but it varies greatly in some of the orders. On each side of the thoracic segment now under consideration, are found two horny pieces, which Kirby and Spence have named plura and periplura. In the latter, the halteres or poisers of Dipterous insects are situated. We have now to consider the organs attached to the thorax, by which motion is effected either on the land or in the air, viz. the legs and wings. The former are never wanting, and theirnumber is invariably the same; the latter are often absent, and when present, their number varies from two to four. Such kinds as possess four wings, are called Tetrapterous insects; those with two. Dipterous; and when altogether wanting, the species are said to be Apterous. The point at which the wings are inserted, has been already indicated ; they articulate to the thorax by means of numerous small pieces. Viewed relatively to each other, the ENTOMOLOGY. 1 1 1 mesothoracic pair is called the anterior, upper, or primary wings ; the metathoracic pair, the posterior, under, or secondary wings. When a single pair only exist, they are attached to the mesothorax, except in one recorded instance, the Aschiphasma annulipes, which has posterior wings without the least trace of an anterior pair. In general form, structure, and relative size, they undergo a great variety of modifications in the diffe- rent orders ; and it is from these modifications that the respective orders derive their names. Sometimes all the four are of similar membranous structure, and either all equal in size, {Neuroptera,^ or the anterior pair largest, {Hymenoptera, &c.) At other times, the anterior are rigid and horny throughout their whole extent, {Coleoptera,) or only on one-lialf of their surface, {Hemiptera Heteroptera.) In some instances, {Orthoptera, &c.) the anterior wings are what is called pergameneous — that is, of a substance between coriaceous and membranous, or somewhat resembling parchment. The harder the substance of which wings are com- posed, the less active is the share they take in flight. When they consist entirely of a hard horny substance, (as among the Coleoptera,) they can be subservient to this use in a very trifling degree ; their primary and important function being to protect the inferior wings and the abdomen. They are, accordingly, distinguished by a name significant of their use, namely, elytra, sheaths or coverings. In proportion as the membranous portion of the wing gains upon the denser part the winpj becomes a more efficient 112 INTRODUCTION TO instrument of motion. From this circumstance^ a gradation can be traced, as to the share the upper wings take in flight from the Coleoptera to the He- miptera, and from these to the Orthoptera. The in- sects possessing the greatest powers of flight, must, therefore, be sought among those in which the upper wings are wholly membranous ; and we accordingly find them among the Neuroptera, Hymenoptera, and Lepidoptera. Every one who has paid the slightest attention to the subject, must have noticed how much more vigorous and sustained is the flight of a dragon- fly, a bee, or a butterfly, than that of a beetle, a grasshopper, or a plant-bug. The under wings are in every instance membranous, and are exclusively organs of flight. A wing of the latter sort, whether it belong to the superior or inferior pair, has the external appearance of a firm, dry, membrane, usually transparent, and traversed by numerous salient horny ribs. Although the membrane appears simple, it consists, in reality, of two membranous leaves, closely applied to each other, and enveloping the ribs just spoken of. This can be made to appear very distinctly when the insect has just emerged from the pupa and immersed in spirits of wine, as the fluid can be introduced between the still flaccid membranes, and thus distends them like a bag. Even this membrane, which appears of the finest and most glossy surface to the naked eye, is found under the microscope to be clothed more or less densely with hairs; and in some gnats* these * See the immensely magnified figure of a gnat in Swam- merdam's Book of Nature, Plate XXXVI. ENTOMOLOGY. 113 liairs assume a lanceolate shape, and spring like small leaflets from each side of the longitudinal nervures. In assuming this form, they make an approach to the scales of the Lepidoptera. These hairs, doubtless, serve the purpose of preserving the wings from the lacerations to which they would be exposed from the nature of the places which the insects frequent for food ; and, particularly, in the case of many of them, when constructing their nests. In addition to this use, M. Chabrier is of opinion that they may likewise contribute to fix the atmospheric fluid on the wings during flight, and thereby increase their buoyancy. The ribs alluded to, ramifying over the surface of the wing, are properly called nervures. They are horny tubes, whose office it is to support and give tension to the membrane. A transverse section shews that they contain a soft parenchyma, and a large spiral vessel, accompanied by a fine nerve. This spiral vessel is a genuine trachea, emanating from the cavity of the thorax, and therefore adapted for conveying air throughout the wing. The nervures are usually uninterrupted, but in some instances, particularly among the Hymenoptera, (especially such as have a petiolated abdomen,) their continuity is frequently broken. This takes place chiefly at the points where they anastomose with each other, and the place where it occurs presents the appearance of a small transparent spot, resembling an air bubble, which led Jurine, who first noticed it, to call it a bulla. The nervures there lose their tubular form, and become scattered in the shape of very fine H 114 INTRODUCTION TO threads^ but immediately reunite and recover their former figure. The substance of the nervures being thus spread over a greater surface, necessarily loses its usual depth of colour, and the transparency which distinguishes these spots is the result. The trachea however, is never interrupted. These interruptions are always accompanied by a slight fold of the membrane of the wing, and when the direction of this fold changes they change along with it. It is thence inferred that their principal object is to admit of a slight distention of the wing, when circum- stances render that necessary, and make it more flexible, the nervures being too rigid for that purpose. The longitudinal and transverse nervures, by in- tersecting and anastomosing with each other, enclose small spaces of the surface of the wing, which are called areolets or cells. These are pretty constant in their forms and position in the several orders and families, and therefore will be described hereafter as aiding in the discrimination and determination of groups. Kirby regards the wings of all insects as divisible into three longitudinal areas, which he names and defines as follows : costal area, the lon- gitudinal portion of the wing that lies between the anterior margin and the postcostal nervure ; interme- diate area, the longitudinal portion lying between the postcostal and anal nervures : anal area, the portion between the anal nervure and the posterior margin. The names given to those parts of a wing which determine its general form, require to be accurately defined. The part by which the wing articulates ENTOMOLOGY. 115 witli the tliorax is called the base; the extremitv opposite to this is the posterior margin ; the anterior or exterior margin, (sometimes called the costa,) is that which is most advanced in flighty lying in the direction of the head, and the interior margin is the one opposite to it. The angles formed by the meet- ing of these margins are, the anterior angle, formed by the meeting of the anterior and posterior margins, sometimes called the apex or apical angle; the posterior angle, formed by the posterior and interior margins ; in the hinder wings this is frequently termed the anal angle. It may relieve the tedium of descriptive and tech- nical details, which are often unattractive although indispensable elements of knowledge, to allude for a moment to the play of fancy in which authors have indulged in regard to the analogical relations which the wings of insects bear, both to certain bodily parts of other animals, and of insects them- selves. Jurine compared them to the wings of birds, and in this he was followed by Chabrier. Latreille, after a laborious investigation, arrived at the unex- pected conclusion, that they are true feet, merely modified in their situation and uses ! Shortly after, M. Blainville discovered that wings are nothing else than exterior tracheae, an opinion which Latreille sub- sequently inclined to adopt. Nearly at the same time, our countryman MacLeay, conceived the no- tion that they represent four of the legs of the de- capod Crustacea. Amid this perplexing diversity of opinion, a German naturalist, M. Oken, comes to 116 INTRODUCTION TO our relief; and solves the difficulty by affirming that memhranous wings are desiccated branchiee ana- logous to the branchiae of fishes ; and, moreover, that elytra are the analogues of the shells of bivalve mollusca ! ! Mr. Kirby is disposed to consider them as having some relation to the membranous expan- sions found in certain Saurian reptiles of the genus Draco ; but wisely refrains from doing more than merely throwing out the hint that such may be the case. It is surely more natural to regard them with M. Audouin, as organs sui generis , destined to exer- cise a particular function, and undergoing such modi- fications as best adapt them for fulfilling that function in every variety of circumstances.* As the wings occupy the superior portion of the thorax, and serve for aerial motion, so the legs are appropriated to the lower, and furnish the means of moving on the earth and in the water. Their num- ber never exceeds or falls short of six ; this rule being so invariable, that any articulated animal found not to conform with it, may at once be concluded not to belong to the class. Their position has been already indicated ; a pair being appropriated to each of the three principal divisions of the thorax, and their distance from each other at the points of in- sertion depends on the greater or less extension of these divisions on their inferior or sternal face. They are distinguished as i\ie fore, middle, and hind legs. The joint which unites the leg with the body is * See Lacord. Intro, a V luntom. I. 409. ENTOMOLOGY. 117 tlie coxa or hip, wliicli is received into an acetabulum or socket^ where it is suspended by a Hgament. Frequently it is of a globular form, more or less sur- rounded and enclosed by a horny substance ; at other times it forms a truncated cone, and appears attached to the thorax by the greater part of its base. When of the former shape, its motions are free and versa- tile; when of the latter, they are more restricted. In intimate connection with the coxa, but capable of independent movement, is a small piece named the trochanter. Its form is subject to many changes^ but it is most commonly triangular or quadrangular, often prolonged into a lateral point. It articulates with the coxa, sometimes by ball -joints entering corre- sponding sockets, or simply by a membrane, the lat- ter being generally the case w^hen the shape is an- nular, as among the Diptera. Its union with the succeeding part of the leg, namely the thigh (femur), is usually much closer. The thigh, in far the greater number of instances, is the largest and most conspic- uous joint of the leg. It is usually thick and robust ; in form cylindrical, or compressed; straight, or arched; slender at the base, and incrassated at the middle or apex, &c. Sometimes the anterior thighs are longest and thickest, (Acrocinus longimanus, Nat. Lib. Coleop. pi. 21, fig. 1,) occasionally the middle pair (^Onitis), and in all the saltatorial tribes, and many besides which do not leap, the hinder pair are greatly enlarged, (Haltica, Locusta, Sagra). The thighs are less frequently furnished with foliaceous and other appendages than that part of the leg next to be il8 INTRODUCTION TO described, but many instances of the contrary will be afterwards adduced. A range, or a double range of spines on the underside is frequently observed, and when these are absent, their place is often supplied by a fringe of hair or strong cilia. The next portion of the leg is the tibia or shank, which, when the insect is in motion, usually forms an angle with the thigh. It is connected with the latter by that kind of articulation called ginglymus. Although frequently as long as the thigh, it is com- monly much more slender. With respect to form, it is, for the most part, slender at the base, and gradu- ally increases in thickness to the apex ; in many in- stances, however, it is of the same thickness through- out. It is often compressed, arched, or flexuose, assuming the latter form to adapt itself to the ine- qualities of the thigh, when it requires, as is fre- quently the case, to be closely applied to that part. A transverse section is most frequently triangular ; sometimes quadrangular or round. The variations in other respects which tibiae undergo, are too numerous to be specified in this place ; but one character is so conspicuous as to claim some atten- tion even in the most general view of their structure, namely, the teeth, spines, and spurs with which they are so frequently armed. The teeth are most re- markable in the fossorial species, and are usually largest in the anterior tibiae ; when very prominent, the part in question is often said to be palmated. The spines are either processes of the horny substance, or they are articulated, and have a free motion ; ENTOMOLOGY. 119 in the latter case, tliey are called spurs (calcaria). The spinous processes are often arranged in a double row on each side of the tibia beneath, having a kind of groove between them ; the spurs are most fre- quently placed in pairs at the extremity or middle. The prevailing arrangement is two at the extremity of each of the tibiae ; sometimes there is only one, and not rarely two on the middle and hinder tibiae, and one on the anterior. The terminial division of the leg is the tarsus or foot, which consists of a series of small, usually heart-shaped or triangular joints, never exceeding five in number. It is connected with the tibia by gin- glymus, and the joints are closely united to each other, 80 as to present a uniform surface beneath. It admits of considerable flexure, a property indispensable for executing the functions that have been assigned to it. The first joint is in general longest, and the last next to it in length ; the fourth (which is often bilobed) shortest. The terminal joint is commonly clavate, and bears either one or two claws at the tip; the latter number being by far the most general. These claws are simple, bifid, dentate on their under edge, or serrate. Between the claws we often perceive a smaller one, which is named the spurious claw { pseudonychia) , and in many families two small membranous cushions are present, which act like sucking cups, and enable the insect to support itself against gravity. Membranous lobes of a similar kind are frequently attached to the underside of the tarsal joints. The whole of the underside (or sole. 120 INTRODUCTION TO planta,) of the tarsus is frequently clothed with very thickly set short hairs^ forming a covering, which has been called the foot-cushion, (pulvillus). Other pe- culiarities connected with this section of the leg will appear when we come to examine it in the dif- ferent orders. The number of the joints has been found to afford very convenient means for forming sub-divisions in the several primary sections;, as they are ascertained to be pretty uniform in nearly allied species. Such as possess five joints in all the tarsi are called pentamerous ; those having five joints in the fore and middle legs, but only four in the hinder pair, heteromerous ; when all the tarsi are four jointed, tetramerous ; three jointed, trimerous ; two jointed, dimerous ; and lastly, such as have only one joint are termed monomerous. Owing to the fore legs frequently presenting a structure different from the rest, adapting them for becoming instruments of prehension, Mr. Kirby thought they made so near an approach to arniSi tliat he applied to them that name. The five por- tions described above, would, in this view, be re- garded as analogous to the clavicle, scapula, humerus, cubitus, and hand. Although many remarkable appearances might be cited in support of this view, yet it is obvious that tbe primary use of these limbs as instruments of motion is never superseded, and we are not entitled to bestow a new name on an organ merely on account of a few slight modifications of structure, or because it has been made subservient to certain additional uses. It is not, besides, in all cases the fore legs that supply the place of arms ; in ENTOMOLOGY. 121 some instances the hind legs are most developed^ and are far most employed in furthering the insect's economy. This may be witnessed in the pill-rolling beetles, (Ateucki.) We have now briefly considered two of the princi- pal sections of the body, the head and thorax, and it only remains for us to bestow a similar notice on the third, namely, the Abdomen. This portion is at once known by the absence of all external articulated ap- pendages similar to those of the anterior segments, and a greater simplicity of composition, consisting merely of several consecutive horny segments or rings, in all cases closely joined, and in some in- stances overlapping each other. The greatest amount of these segments is nine ; for the entire number in an insect never exceeds thirteen, and of these one is formed by the head, and three are occupied by the thorax. It often happens, however, that the number seems much less, in consequence of several being united, or so overlapping each other that they cannot be observed. In general the dorsal segments seem more numerous than the ventral ; although the reverse of this obtains in some instances. A difference in this respect is not unfrequently a sexual distinction. The shape is too various to admit of a determinate definition in a few words, but a trans- verse section very generally makes an approach to a rectangular triangle, the base being uppermost. The mode of attachment to the thorax is nearly the same in all cases, although there is an apparent difference depending on the shape of the basal portion. When the latter is broad, as in conical shaped abdomens. 122 INTRODUCTION TO the base appears united by its whole circumference to the metathorax, a suture alone indicating the point of junction; in such cases the abdomen is said to be sessile. A very narrow point, in other instances, forms the whole bond of connection, the base being contracted into a slender trumpet-shaped tube, which scarcely appears of adequate dimensions to transmit the vessels requisite for maintaining life ; such an abdomen is said to be petiolated. The segments of the abdomen may be regarded as composed each- of two arches, a dorsal and a ventral one; but analogy inclines us to believe that these are made up of several subordinate parts, although it is often impossible to point out their boundaries. In the StaphylinidcBy for example, there is a lateral portion, in the shape of a parallelogram, on the upper side of each of the ventral arches, united by a line or articulation to the membranous part. These pieces, which M. Strauss was the first to notice, and which he named lombar pieces, (pieces lombaires,) are pro- bably analogous to some of the lateral plates of the thorax. The segments articulate with each other in two principal ways. In the first, the superior arches cover each other more or less, or simply touch at the edges, while the lower ones are soldered together by the middle, and the sides alone left free. The result of this arrangement necessarily is, that the former alone are susceptible of dilatation, and the abdomen greatly restricted in its powers of expansion and movement. In the second, each segment is covered by that which precedes it without any union at any part, so that they slide into each other like the tubes ENTOMOLOGY. 123 of a telescope^ and can readily be moved in any direc- tion. Such a confirmation is well exemplified by the Staphylinidae, which elevate and twist about their abdomen with the utmost facility, and even turn it over the back to push the wings under their short cases.* The whole of the segments are lined in- ternally with a soft membrane, which connects them, and retains them in their places, without im- peding their movements. This membrane becomes visible when the abdomen is in a distended state, as in a gravid female, when the abdomen seems to form a bag, with horny plates arranged in a certain order over its surface. An opening for the respiratory organs, which ramify through the body, may be observed near the lateral margin of each segment. These openings are surrounded with a hard ring, and are called spiracles or air-holes, {Stigma, Spiracula.) It has been well observed that each of the three great divisions of the body is the appointed seat of a separate set of organs, all of them alike important in the animal economy. As the head contains the organs of mastication, and the thorax those of mo- tion, so the abdomen is the appropriate site of the generative organs. These, however, are chiefly in- ternal, and will be most conveniently considered when treating of the anatomy of the abdomen. Such external appendages, too, as are more or less acces- sory to the organs alluded to, as well as various others which, as far as known, have no connection with * See Lacord. Introd. I. 447. 124 INTRODUCTION TO ENTOMOLOGY. them further than that of juxta-position, will full under our notice afterwards. Eaiplanatioti of Plate Irf Fig. 1. Head of Mylabris, upper side : — a, forehead ; 6, vertex ; c, occiput ; c?, c/, temples ; e, e, eyes ; /, torulus, cavity for the insertion of the antennae ; <7, clypeus, (of Fabr.) nose, (of Kirby,) Epistome of Latreille ; ^, labmm. Fig. 2. Under side of same head : — A-, posterior orifice ; Z, the neck ; ni, the mentum ; o, the eyes •, p. mandibles ; s, labial palpi. Figs. 3, 4, 5. Forms of the Labrum : — Fig. 6. IMandible of Hydrous piceus ; Fig. 7. Do. of Goerius ; Fig. 8. Do. of Calosama sycophanta. Fig. 9. Maxilla oi Necrophorus germanicus : — a, maxillary pal- pus ; 6, external lobe of the maxilla ; c, internal lobe. Fig. 10. Maxilla of Cicindela : — a, external maxillary palpus ; b, internal do. or exterior lobe of the maxilla ; c, inte- rior lobe, with an articulated hook at the apex, d. Fig. 11. Maxilla of Hydrous piceus : — a, insertion or hinge; 6, dorsal piece ; c, squame palpifere of Strauss ; 6, c, d, taken together form the stalk, (ttipcs;) e, external lobe; /, internal do. Fig. 12. Labium of Cychrus rostratus : — a, mentum ; 5, ligula ; c, c, labial palpi. Fig. 13. Labium of Carabus, inside : — a, mentum ; b, lingua ; c. paraglossae. Fig. 14. Thorax of Scoliaflavi/rons, upper side, the red colour indicating the prothorax, blue the mesothorax, and yellow the metathorax ; coxae, green : — A, the prono- tum ; C, the mesonotum ; c/, d, patagia; c, scutellum ; F, the metanotum ; H, H, the parapleura. Fig. 15. Side view of the same : — E, mesostemum ; B, prester- num ; G, metasternum ; rf, patagium ; c, scutellum ; a, first spiracle ; /S, second do. Fig. 16. The same from beneath : — B, B, prostemum ; E, E, mesostemum ; G, G, metasternum. Fig. 17. Thorax of Cicada Fraxini : — A, pronotum ; C, meso- notum ; c, scutellum ; rf, c/, frenum ; F, F, metanotum. Fig. 18. Hinder leg of Melolotitha vulgaris: — a, b, coxa; d. trochanter ; e, thigh ; /, tibia ; A, tarsus ; t, claws. Fig. 19. Pectinated claws. Fig. 20. Claws of an Asilus : — o, central filaments ; s, s, membranous expansion of the terminal joint advanced beneath the claws. 125 ANATOMY AND PHYSIOLOGY OF INSECTS. Having thus traced the progress of insects from the time of their birth till they arrive at their full matu- rity, and likewise noticed the most remarkable fea- tures in their external conformation, it now becomes requisite to advert to their internal structure, and give a comprehensive view of the complex system of organs by which life is maintained. In these a very close analogy, for the most part, exists to the vital system of the higher animals ; but in some respects curious and most important differences prevail. View- ing the animal kingdom as forming a progressive series, from the most simple to the most complex organism, insects may be regarded as occupying nearly the centre of the scale ; for, though some pro- perties might entitle them to rank higher, there are others in which they are so deficient, as completely to counterbalance that consideration. In muscular vigour, for example, and the complication of the digestive canal, they are almost equal to the verte- brata, while the circulating system is so imperfect, that it was, till lately, a matter of doubt whether it deserved the name. From these considerations, it may be inferred that the systems of organs ai'e neither very complex nor very simple, and that in these re- spects, there is some degree of inequality among them. 126 ANATOMY AND PHYSIOLOGY They may be considered, together with their res- pective physiological functions, under the following heads: 1. Nutrition; 2. Sensation; 3. Muscular System; 4. Reproduction. Nutrition. — As nutrition consists in the renewal of the molecules which constitute an animal body, and as that is accomplished by means of the food, we have only to consider the principal processes which the latter undergoes, in order to obtain an indication of the different heads linder which this department of the subject may most naturally be treated. The first of the most important changes to which the food is subjected internally, is its conver- sion into chyle, previous to which it is incapable of affording any nutriment ; this process is called diges- tion, and takes place in a special organ named the alimentary canal. But the chyle is not perfectly adapted to its nutritive functions till ithas been brought into contact with the atmosphere, in order to receive a supply of its vital principle, viz. oxygen. There being no lungs in insects to which it can be conveyed, as to a reservoir, to receive this supply, the necessity is provided for by bringing the air into contact with it by means of small tubes ramifying through the body ; this process is called respiration. In conse- quence of the blood being aerated at so many places, instead of a particular point, often remote from the extremities, there is no necessity for a rapid or general circulation of it ; still, however, it is by no means stagnant, and its movement is called, although the term is rather too strong, the circulation of the blood. OF INSECTS. 127 In the different stages of the nutritive process, cer- tain substances are formed, which are sometimes essential to the animal economy, and at other times rejected as hurtful, these may be included under the general name of secretions. We shall successively advert to each of the subjects just enumerated. Digestion. — As this function is almost entirely devolved on the organ named the alimentary canal, we shall endeavour, in the first place, to convey an accurate notion of the form and position of that im- portant viscus. It may be described generally as an elongated tubular organ, occupying the centre of the body, and open at both extremities. Occasionally it is nearly straight and not longer than the body, but, in most instances, it is twisted on itself in numerous convolutions, and its length is consequently very considerable, sometimes twelve times as long as the body. In this respect it is found to vary, as among the higher animals, according to the nature of the food, being long and complicated in herbivorous spe- cies, and comparatively short in such as live by prey ; but even this law is not without numerous and striking exceptions. In most cases the form is rendered irre- gular by many distentions and constrictions, which are so conspicuous that they may be regarded as dividing the canal into several parts, which have received diffe- rent names according to the functions they perform. The place occupied by the canal is the median line of the body, immediately beneath the dorsal vessel. (See PI. II. fig. 1, h, c, d, e,f.) Its texture is not the same throughout its whole extent, but its essential con- 128 ANATOMY AND PHYSIOLOGY sists, as among vertebral animals, of three tunics or coats, the mucous, cellular, and ^nuscular, the first being internal, and the others superimposed in the order in which they have just been named. The first is dehcate and soft, without any decided texture, frequently transparent, and of such tenuity that its presence is not always easily detected. The second layer, (which Strauss names membrane propre, or proper skin,) is likewise for the most part smooth and thin, although it sometimes becomes thicker and spongy. It is generally almost without fibres, but, when highly magnified, a few globules or granulations appear, arranged transversely in its tissue. These have been called by Strauss, gastric glands. Accord- ing to Leon Uufour, the membrane in question is entirely wanting in hemipterous insects. The mus- cular membrane is firm, fibrous, and contractile, sur- rounding and protecting the exterior, and distinct longitudinal and transverse vessels pervade its tex- ture. It is it which causes the peristaltic movement of the digestive tube, and it forms the contractions and sphincters observable in different parts of it. These contractions, as already intimated, form various divisions in the intestinal tube which have names assigned to them in accordance with their functions. The following divisions are recognised, the pharynx, the esophagus, the crop, the gizzard, the chylijic ventricle , the slender intestine, the coecum, and the rectum. Besides these integral parts of the canal, there are various vessels appended to itj which discharge juices OF INSECTS. 129 into it which are indispensable to complete the act of digestion ; these are the salivary ^ hepatic or biliary vessels : along with which the urinary vessels will be noticed. Before proceeding to the separate consideration of each of these parts, it is of importance to remark that they never all co-exist in the same species. Sometimes one is absent, sometimes another, and they are often found to differ materially in the same individual^ according as we examine it in the larva or perfect state. The pharynx cannot be very decidedly distinguished as a distinct feature, as it merely forms the distended aperture of the canal where it opens into the cavity of the mouth.* Indeed, it cannot be said to exist at all except among the mandibulated tribes, for, in a suctorial mouth, the esophagus is in strict contin- uity with the sucking tube ; it can only be defined therefore as the distended opening of the esophagus in masticating insects. The mouth and pharynx are usually upon the same plane, but in such insects as chew the food for a length of time, it lies a little higher, doubtless for the purpose of preventing the aliment finding its way into the esophagus before * Singular as the assertion may appear, some insects exist in which the alimentary canal has no opening at its anterior extremity. These are the bot-flies, constituting the genus CEstrus, which are, of course, incapable of taking nourishment. In a few instances the canal has its hinder extremity closed, as is exemplified by the larvje of wasps and bees ; these take nourishment, but require to void no un assimilating matter. I 130 ANATOMY AND PHYSIOLOGY being sufficiently masticated. The part last named, otherwise called the gullet, (PI. II. figs. 2, 3, a,) is a narrow tube intermediate between the pharynx Cwhen such exists,) and the crop, or, in the absence of the latter, the gizzard. It commonly passes through the thorax in a straight line, and terminates at the origin of the abdominal cavity ; but nothing can be more variable than its length. In certain Hymenoptera, ( Pimpla, Pompilus,) it forms more than half of the entire canal; in the cockchafer, (PI. II. fig. 3, «,) a small portion behind the head, scarcely one-sixtieth of its length ; and all intermediate dimensions occur. The esophagus is in all cases simple, except among the Lepidoptera, which present the remarkable pecu- liarity of a bifurcation anteriorly, a branch emanating from each of the two spiral sucking tubes and uniting into one conduit, usually just behind the head. The crop, (PI. II. figs. 2, 3, b, b,} has been so named by Cuvier, Leon Dufour, and Strauss, because it occupies the same position as the organ so called in birds ; by some other authors it is denominated the stomach. It appears, for the most part, as a simple dilatation of the hinder part of the esophagus into a kind of bag, which is usually on a line with the other parts of the alimentary canal, but sometimes appears suspended at the side like a pouch. Its form is most variable, even in the same species, according to the degree of its repletion or vacuity. When the gizzard, the succeed- ing portion of the canal, is wanting, which is very often the case, the crop appears in its simplest form, and is unprovided with any secretion to act upon the OF INSECTS. 131 food ; but when the part alluded to exists, the crop is furnished with interior glandular organs which se- crete an active juice. These glands are most con- spicuous among the tiger-beetles, {Cicindela) even appearing in external rows on the obcordate shaped crop. (Plate 11. fig. 2, b.) With very few excep- tions besides this, the surface of the crop is quite smooth. These remarks, however, apply to tliis part only as it appears among masticating insects; in all other kinds, with the single exception of the Hemiptera, it becomes (or there is substituted in its place, according to the views we adopt regarding its origin,) what has not improperly been called a sucking-stomach. (Plate 11. fig. 4, c.) Its function is no longer to receive the alimentary substances trans- mitted from the mouth, but to facilitate the rise of the fluids from the mouth to the principal receptacles of the alimentary canal. This it promotes by dis- tending at the will of the insect, and thus rarifying the air in its interior and acting as a kind of pump. It presents various modifications of form in all the dif- ferent tribes possessing it. The crop is succeeded by the gizzard, (Plate II. fig. 2, c.) which may always be recognised, when present, by having its internal sur- face covered with teeth, spines, or horny ridges ; a structure which eminently fits it, in connection with its muscular, almost cartilaginous texture, for sub- jecting the food to a more complete trituration than it had previously undergone. It exists in all insects that feed on hard substances, such as wood, bark, &c., and in all carnivorous kinds; but not in those 132 ANATOMY AND PHYSIOLOGY that derive their nourishment from decomposed vege- table or animal matter. For the most part, only tvi^o of the membranes which enter into the general composition of the tunic of the intestinal canal can be detected here, the innermost of which is almost corneous and much folded. These folds are not accidental, but are arranged in a certain order, according to the genera and families. The gizzard is wanting in the larvae of all insects which go through a complete metamorphosis. The chylific ventricle, (Plate 11. fig. 2 and 3, d,) is the ensuing dilatation of the intestinal canal ; an important cavity which, upon the whole, may be regarded as most nearly corresponding "to the stomach of the verte- brata. The above name, assigned to it by M. Leon Dufour, is exactly expressive of its function, which is to contain the food, now reduced to a homo- geneous and impalpable pulp, till it undergo the pro- cess of chylification. Its capacity is considerable, either arising from its width or length. Its termina- tion behind is indicated by the insertion of the biliary vessels, or by a constriction separating it from the small intestine. In form, it is always more or less tubular, or tending to oval, but even within these limits the shape varies much. In the common cock- chafer, (PI. II. fig. 3 d,) it is contracted behind into a long tube, and twisted into several circumvolutions — a mode of disposition which it frequently exhibits in a still more complicated manner in some of the other orders. One of the most distinctive and remarkable characters of this ventricle, is the palpillae or small OP INSECTS. 133 bags appended to its surface in certain tribes. They produce the appearance of a coarse villosity, (PI. II. fig. 2d,) but when examined with the microscope, they are found to be little bags, opening into the ventricle. They are formed by the internal mucous membrane, the other membranes not entering into their composition. The greatest diversity of opinion prevailed among physiologists respecting the func- tional uses of these appendages, but it seems now to be the most generally received opinion that they are secerning organs, and that their secretions act as solvents on the contents of the ventricle, particularly when these consist of animal matter, for it is among the cranivora that they are principally found. Other appendages sometimes occur characteristic of par- ticular races. The remaining portion of the nutrimental canal may be called the intestine. It is always more sim- ple in form, considerably narrower, and more deli- cately constructed than the preceding divisions. The slight expansions and contractions which it offers in certain parts of its course, have led some to regard it as consisting of nearly the same portions as the in- testines of the vertebrata, and they consequently re- cognise a duodenum, an ilium, a csecum, a colon, and a rectum. If we were perfectly acquainted with the functions of these organs in insects, as has been judi- ciously remarked, it is possible that we might find reason for these numerous divisions, each having a special function alloted to it ; but in our present un- certainty in this respect, we run less risk of error by 134 ANATOMY AND PHYSIOLOGY adhering to the more simple division and nomencla- ture indicated on a former page. It will he seen, moreover, that two of the parts which we have not regarded as entitled to a separate consideration, the duodenum and the colon, are thought to exist in only a very few species, and even then they are not par- ticularised by any one constant character. The intestine commences immediately behind the chylific ventricle, from which it is separated by an nnnular constriction or sphincter. This alone points out its origin, when the biliary vessels are placed towards the anus ; but being usually inserted imme- diately beneath the sphincter in question, they then mark precisely its anterior limit,* The small intes- tine, in its ordinary state, is a slender simple tube, very variable in length. In general, it is a good deal shorter than the body, frequently shorter than the chylific ventricle, (as in the ChrysomelidcB?) some- times it attains the length of the body, and in a few instances exceeds it. In certain cases it deviates from a simple tubular form, and becomes inflated more or less abruptly into a clavate or oval-shaped bag. This is well exemplified in the common cock- chafer, (Plate II. fig. 3^) Adhere it forms a large ovoid pouch, and presents, when distended, five pro- jecting ribs, which correspond to a series of im- bncated plates in the interior. In this case there is an additional inflation, of much smaller size, a little behind the principal one. " If the name of this por- * Lacord. Intro. II. 33. OP INSECTS. 135 tion of the intestine/' says Burmeisterj speaking of that part which corresponds to what we have called after the French physiologists, the small intestine, *' is to be determined from its divisional distance from the stomach, it must he considered as the true ilium, which is however contradicted by its function, which, like that of the ceecum of the glires of the mammalia, subjects the food to a second digestion and. extraction before it is rejected. We are convinced of this by the comparison of its state in the stomach, and in this portion of the canal, for we find it here much more pappy than there, but not so viscous as in the colon." * The Ccecum (PI. II. fig. 2 y.) is that portion of the canal, behind the small gut, where the unassimilated parts of the alimentary substances, now completely deprived of their nutricious particles, begin to acquire a. hard consistency, previous to their expulsion by the rectum. It is generally a direct continuation of the small intestine, but it is divided from it by a valve, which completely shuts up the opening. In some cases, however, the intestine is united to its side, and it forms a large ovoid vessel, as in Dytiscus Roeseliij and allied species. The external surface is frequently covered with papillee, and the internal, particularly near the mouth of the small gut, with glandular warts, which are supposed to secrete a fluid to assist in the expulsion of the fecal matter. This segment of the canal is usually short, but it varies too much to admit * Manual of Entom. : Shuckhard's Trans. 139. 136 ANATOMY AND PHYSIOLOGY of its relative dimensions being easily stated. The same remark applies to its form, although it most commonly inclines to oval. Its situation is more con- stantj for it always occupies the hinder segment of the abdomen. It frequently has a pouch-shaped appendage, originating at its commencement, which sometimes appears quite distinct from it, although their cavities are always connected with each other. In this case there is no valve to separate it from the caecum. From its having been noticed in all perfect aquatic insects, M. Leon Dufour regards this appen- dage as a kind of swimming bladder ; but to this view there are great objections, among others, that which arises from the consideration that air could not have ready access to it. It is more probable that it is in some way subservient to defecation. The rectum is nothing more than the terminal portion of the caecum : it is always short, and provided with a sphincter or strong annular muscle, which closes the aperture when not in action. Its muscular tunic is very thick, its parietes very variable in form, and it is from them that the excrements acquire their particular figure. Having thus noticed the divisions of the great nutrimental tube, leaving some peculiarities to be noticed when treating of the respective tribes in which they appear, it is now necessary to advert to its appendages, which were stated to consist of the salivary, biliary, and urinary vessels. Insects are seldom provided with glands, properly so called, as a necessary consequence of the want of a perfect OF INSECTS. 137 circulation ; their secreting and excreting organs are usually long, slender, and tubular vessels, floating freely in the interior of the body. The salivary ves- sels are most conspicuous among suctorial insects, but they likewise exist in others. They generally lie around the pharynx or the crop, and ascend into the cavity of the mouth by a meandering duct. Un- der all their changes of form, we can, without much difficulty, according to M. Leon Dufour,* recognise the following parts: 1. A glandular apparatus des- tined to secrete saliva, which is single, double, or even triple ; 2. One or two excretory conduits, whose function it is to discharge the secreted liquid into the mouth or esophagus ; 3. Bags or reservoirs in which the saliva is deposited and preserved. In Scutellera nigrolineatay the figure of which we have copied from the author just named, all these parts are distinctly exhibited. PI. II. fig. 5, a, a, represents a large semi-diaphanous glandular piece, (greatly resembling a true gland,) composed of two lobes, the hinder of which is digitated ; from each of these issues a very flexuose excretory duct, which debouches into the esophagus, (,7 Africa, .... 2,942 674 4,3 New Holland, . 320 162 2,0 Order II. — Orthoptera. In immediate succession to the order of ^^^hich we * In making this attempt, it was of course necessary that as nearly as possible the same extent of the different countries should be compared with each other. ORTHOPTERA. 207 have just been treating, most authors agree in placing the important one above named. This position, in the series of ordinal groups, it has obtained in con- sequence of presenting many properties in common with the coleoptera ; some of the older entomologists, indeed, regarded them as so closely allied, as not to admit of separation. But this opinion could only result from an imperfect acquaintance with their re- spective characters ; for in the present instance, the peculiarities are sufficiently distinctive and important, fully to entitle this order to the rank which it now holds. The name having been applied in conformity with what has been called the Alai-j/ system in entomology, has reference to the nature and peculiarities of the organs of flight. These are found to be folded longi- tudinally when at rest, and o^^kg straight, crrgga wings, affords a term indicating this disposition. As in the preceding order, the wings are four in number. The anterior pair are of a pretty stiff substance, resembling parchment, serving both for the purpose of protecting the inferior wings, and also assisting in flight. In the former respect, they perform the same service as elytra, but in the latter share in a function to which elytra cannot be said to be directly subservient. In- stead, therefore, of having that name applied to them, as is often done, it is better that they should have a distinctive appellation of their own; and of the various terms that have been used, tegmina seems the most appropriate. In far the greater number of instances^ they do not form a straight line along the back, where 208 SYSTEMATIC ARRANGEMENT. the inner edges approximate when closed, hut the one usually overlaps the other. Although, for the most part semi-membranous, they vary considerably in consistency in different tribes. In certain species of Mantis, for example, they nearly assume the appearance of transparent reticulated wings, while amorg the convex-backed Blattce they approach to the rigidity of elytra. They are generally re- ticulated by a series of strong nervures, radiating from the base to the summit, and crossed by a multitude of smaller ones, resembling fine lace. Sometimes, however, these nervures are visible only at the apex of the tegmina, but their existence is always obvious on the under side. Among the Grylli, the males of which are provided with a musical apparatus, situated at the base of the abdomen, some of the nervures are much more prominent than others, and instep d of beino; longitudinal, are curved in a variety of ways ; it is by rubbing these against the apparatus mentioned, that these insects produce the peculiar noise for which they are remarkable. The under wings being adapted solely for flight, are of a much more delicate texture than the superior pair. They are traversed by a series of pretty strong parallel nervures, diverging from the base, and are folded up and expanded nearly in the same manner as a fan. From this cause they cannot be packed in so small a compass as in beetles, the wings of which are folded transversely upon themselves ; ac- cordingly, they are not always quite covered by the tegmina when at rest, and in some instances they ORTHOPTERA. 209 project beyond the extremity of the body, producing the appearance of a tail, as may be seen in Gr^llus, Gryllotalpay &c. This order is one of those in which the mouth is said to be perfect — that is, having all the constituent or essential parts that exist in the most typical tribes fully developed. Not only is this the case, but they are likewise of a hard or osseous consistency, appa- rently fitted for all the functions they perform among the coleoptera, and shewing no tendency to become obsolete, as is the case with those orders at the oppo- site extremity of the series. The description, there- fore, that has been already given of the oral organs of the coleoptera, will serve to convey a general notion of their appearance in this order, and super- sede the necessity of adding much to what has been already said. The upper lip, (Plate VI. fig. 2, d, and fig. 3,) in general, is very conspicuous, and, as in all other orders, very variable in its shape. It is somewhat peculiar in orthopterous insects, by being frequently unequal on the surface, occasionally ciliated, or pro- vided with tufts of pretty long hair, and armed with teeth on its anterior edge. As might have been expected in insects, many of which have long attracted observation by their ex- tensive depredations on vegetable substances, the mandibles are large, powerful, and efficient. They present the ordinary forms, being more or less tri- angular, arched on the outer side, and armed with teeth on the inner edge. If Marcel de Serres' ob- 21 SYSTEMATIC ARRANGEMENT. servations be correct, which they are admitted to he in general, the mandibular teeth of the Orthoptera offer this peculiarity, that they have a coriaceous and transverse plate, (lame) at their base, which seems to separate them from the body of the mandible ; whereas in other cases, the teeth are well known to be only projecting pieces of the substance of these organs. The same observer, adopting an idea first started by Knoch, regards these dentations as bearing so close a relation to the mode of nourishment, that by observing their structure, distinct intimation may be obtained of the kind of food used, and conse- quently in some degree of the habits of the respec- tive species. He divides them according to their analogy to the dental system of mammiferous ani- mals, into incisive, canine, and molar. The former are large, somewhat resembling a curved wedge, their external surface convex, and the opposite one con- cave ; a form which renders them eminently fitted for cutting : the teeth at the extremity of the mandibles of Locusta exemplify this modification. The canine teeth are conic, often very sharp, and lengthened, and are of course characteristic of such genera as Empusa and Mantis, which are purely carnivorous. The molars are large, short, and fitted for bruising alimentary substances. Never more than one exists in each mandible situated at the base opposite to each other. The species provided with the first and last mentioned description of teeth are herbivorous; and when they exist simultaneously, Avhich happens occasionally in such species as are ORTHOPTERA. 211 omnivorous, they are usually of small dimensions. (Plate VI. fig. 4, mandibles of the house cricket with incisive teeth. Fig. 4^'^, one of the mandibles of Acrydium, with a large molar plate near the internal base, b.) The organs which next require to be noticed, are the maxillce or under jaws. As they arc employed for a similar purpose as the mandibles, they have a corresponding development ; they are in fact often of large size, and in their general forms not unlike those of the carnivorous coleoptera. They are always glabrous in this order, or clothed with such short hairs as to be almost imperceptible. The maxillary palpi, (Plate VI. fig. b, c) are always five-jointed in this order, whereas the normal numxber among the Coleoptera appears to be four. The portion called the blade of the maxilla, is that which forms the apical extremity ; it is usually incurved and bifid at the tip, (Plate VI. fig. 5, a.) It bears externally a distinct lobe, corresponding to what are frequently descTibed as internal maxillary palpi. The name galea or helmet is now applied to this piece, (Plate VI. fig. 5, b.) It is frequently palpiform, consisting of two joints, and in some instances, (as in Acrydiunfi) apparently of three ; but in all cases it is dilated at the extremity somewhat in the form of a helmet, being vaulted, and covering the apex of the maxillae to which it is usually closely applied. This is an important piece owing to the part it takes in nutrition, and the pennanence of its forms in different species. The labium or under lip is rather of a more com- 212 SYSTEMATIC ARRANGEMENT. plex structure, and the nomenclature of its separate parts somewhat involved. On examining the figure of the lower lip of the domestic cricket, (PL VI. fig. 6) it will be observed that it is divided into three distinct parts by means of well defined lines. The basal portion, {a) by which the whole labial apparatus is attached to the head, Kirby regards as the mentum. The second division (d) he considers as more directly answering to what is strictly called the labium in other insects ; and the terminal portion i^e) is merely an additional articulation to it, divided into two, three, or more lobes. '' At first you would imagine the terminal part of this organ to be the analogue of the tongue, or ligula F ; as it is indeed generally regarded by modern Entomologists. It seems like the tongue of the Carabi L, Di/tisci, &c. to be a distinct piece, which has below it both labium and mentum : but when you look within the mouth, you will find a linguiform organ, which evidently acts the part of a tongue, and therefore ought to have the name j and the piece just alluded to must either be regarded as the termination of the lip, or as an ex- ternal accompaniment of the tongue, analogous, it may be, to the paraglossce in bees." * The labial palpi are variously described by authors as consisting of three or four articulations. The number of joints is certainly alike in all the species, and the discrepancy alluded to, has probably arisen from some observers having included the minute • * Introd. to Entom. III. 424. ORTHOPTERA. 2 1 3 radical joint in their enumeration, while others have overlooked it, or regarded it merely as a point of support to the palpus. Although frequently almost lost in the substance of the labium, this joint appeal's however to be always present, and although ap- parently three-jointed, the palpi must therefore be regarded as really composed of four articulations, (Plate VI. fig. 6, c,c.) The tongue, {lingua,^ generally a very obscure member of the oral appendages, is very distinct in some of the insects of this order. It is short, re- tracted within the mouth, rather of a soft substance, and in some instances, as in Blatta and Locusta^ it bears a pretty close resemblance to the tongue of a vertebrate animal. The modifications of the antennae will be specified afterwards as aiding in the discrimination of the different groups. In general they are long, setace- ous, and extremely flexible, consisting of fourteen, sixteen, or twenty-five joints among different species of Locustee ; of above thirty among the Mantes ; while in the Blattee or Cockroaches, the articulations sometimes amount to 150, and vary even in indivi- duals of the same species. Besides the ordinary compound eyes, which in general are large and prominent, the insects of this order are mostly provided with three simple eyes situated in the crown of the head. In the genus Blatta, the domestic cricket, and some other in- stances, these auxiliary organs are wanting, but there is a subdiaphanous space over the base of the antennse 214- SYSTEMATIC ARRANGEMENT. in Blatla which may be regarded as representing them. The dypeu8 or shield is always distinct among the Orthoptera, (Plate VI. fig. 2, c.) In several families of this order, ^^ the suture, uniting the shield with the upper part of the skull, is membranaceous ; hence the lip and shield move simultaneously with the mandibles in mastication. This is a departure from the general law of nature, and its occurrence is well worth remarking ; as the motion of the shield might induce an observer to suppose it the lip, which would consequently become a new and supernumerary ele- mentary part." * Of the three segments composing the thorax, the prothorax is often very much developed, to such a degree indeed, that in a particular group of the old genus Gryllus it sometimes exceeds in size all the rest of the insect. The mesothorax is very incon- spicuous in this order, for the reason, that the fore- wings do not take a very important share in flight, and the part which supports them therefore admits of diminution. It is scarcely observable, indeed, when the wings are closed, except in certain species of the Mantis tribe. The metathorax, which is seldom so much developed as the preceding sections in the generality of insects, here acquires considerable pro- minence, and in certain Phasmae seems to have at- tained its maximum. The metamorphosis of orthopterous insects, is what * External Anat. of Ins. Ent. Mag. vol. IT. 65. ORTHOPTERA. 215 is technically called semi-complete — that is to say, the changes in external form^ which they undergo in their transition fi-om one state to another, are only half so considerahle as those which take place in some other instances — the Lepidoptera for example. In fact, it is difficult, in many instances, from inspecting an in- dividual to say what stage of its progress it has reached. The final state, however, may usually be determined by the full development of the wings and tegmina j these members exist in the pupa only in a rudimentary condition. The pupa is never quiescent, but moves about and takes food. Not only do the larva and pupa resemble the perfect insect in exter- nal appearance, but it is likewise found on dissection that their internal organisation is similar. In the penultimate and antepenultimate states, the sexes are likewise distinct, and copulation sometimes takes place, but it is improbable that this premature union ever proves productive. The transformations in question, therefore, must be considered as merely a series of gradual approaches to perfection, none of • the transitions being marked by any decided change of general form, the only consequences resulting from ecdysis, or casting of the external crust, being in- crease of size, slight development of certain parts, and an aptitude to continue the species. This order is one of the least numerous in species. But its poverty in this respect is in some measure compensated for by the great amount of individuals of tlie same species, the swarms of locusts, grass- hoppers, and cockroaches, which sometimes congre* 216 SYSTEMATIC ARRANGEMENT. gate, probably exceeding every other assemblage of the insect tribes. In this country, not more than about fifty indigenous Orthoptera have hitherto been detected_, and it is not likely that any considerable number have escaped the researches of modern collectors. Although these insects must, of course, present a pretty general agreement in all essential parts of structure sufficient to justify their arrangement in the same division of their class, they are certainly very dissimilar in external aspect. The genera For- ficula, Blatta, Locusta, and Phasma, bear almost as little outward resemblance to each other as the species of any tvt'o separate orders. It was this circumstance that led Dr. Leach to propose its division into three different orders, Dermaptera, including Forficula ; Dictyoptera, including Blatta, and distinguished by the tegmina overlapping each other on the back ; the other tribes to be referred to Orthoptera. The first of these has been since admitted by some authors to the rank of a separate order; among others, by Mr. Westwood, who names it Euplexopteray because the term Dermaptera is said to have been completely misapplied by English Entomologists, having been originally proposed for the Cimicidse. Notwithstand- ing the peculiarities in its structure which have led to this step, it is difficult, we think, to examine the earwig without being convinced that it is essentially an Orthopterous insect ; and as that order must, in any case, be defined with considerable latitude, it can scarcely be regarded as an undue extension of it ORTHOPTERA. 2 1 7 to include the Forficulidse. Dr. Burmeister, and some other of the modern continental naturalists, are decidedly opposed to any other step, regarding the distinctive characters as of no higher value than family ones. It is certain that if the principles on which the insects in question are separated from the Orthop- tera, were in every case acted upon, the amount of ■orders would be at least double what it is at present. But whatever may be thought of the expediency of multiplying the great primary divisions of the class, the differences alluded to afford a ready means for dividing the order, as it now stands, into several well defined and very natural families or subordinate groups. Several of these are so strongly marked, that according to the ingenious observation of Pro- fessor Lichtenstein, the Jewish lawgiver, when he delivered his instructions to the Israelites, regarding the kind of food they were to use, distinguishes, as clean insects, the Fabrician genera, Gryllus, Locusta, Truxalis, and Acheta. " Yet these may ye eat of every flying-creeping thing that goeth upon all four, which have legs above their feet to leap withal upon the earth ; even those of them may ye eat; the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind." '" Although Moses may have been led to do this non sine adflatu divino, still the discrimina- tion, as Mr. Kirby remarks, presupposes a knowledge of their general characters in the people to whom the * Leviticus, ch. xi. 21, 22. 218 SYSTEMATIC ARRANGEMENT. precept was addressed, to whom it would otherwise have been de ignotis. They naturally divide themselves into the following tribes, to each of which we shall successively advert, presenting a view of its general history, and illustrat- ing it, in most instances, by figures of some of the most characteristic species : — Forficulidse, {earwigs,) Blattidee, {cockroaches,) ]\Iantidae, {soothsayers or 7oalking -leaves,) Phasmidse, {spectres,) Gryllidse, { grasshoppo'S,) Locustidse, {locusts,) Achetidse, {crickets.) The first four of these, being all provid- ed with feet formed for running, constitute Latreille's comprehensive family Cursori a; the three last, which have thickened hinder legs adapted for leaping, com- pose his family Saltatoria. Fam. Forficulid^. The forms and appearance of the common earwig are so familiar to all, that we have thought it unne- cessary to figure any of the species, especially since they are all very similar to each other ; but as they present several peculiarities in their structure and habits, it is necessary to give some account of them, otherwise our exposition of this order would be in- complete. It has been already mentioned, that the disposition of the wings does not correspond to what is observed in other Orthoptera, since they are folded both longitudinally and transversely.* This arrange- * Although the character afforded by the folding of the ^ngs must be admitted to be a valuable one, its importance is obviously over-estimated when it is regarded as authorising ORTHOPTERA. 21.9 ment is rendered necessary by the extreme shortness of the tegmina, which would otherwise be quite in- adequate to cover any considerable portion of the wing, and the latter would be exposed to continual injury. The tegmina are square, resembling the elytra of one of the Staphylinidae, without veins, and the wings are somewhat ear-shaped, the nervures radiating from a point not far from the centre of the anterior border. The maxillary palpi are five jointed, but the terminal joint is very minute. The ligula is forked ; the antennae filiform, varying in the number of articulations from twelve to thirty, in different species, and even in different stages of the same in- dividual. Besides the common earwig, {F.auricularia,) there are at least four other species indigenous to Britain, and others are found in foreign countries ; all our native kinds, however, are rare, except F. minor, (constituting the genus Labia of Leach,) which occurs not unfrequently, and is usually observed on the wing, which is not often the case with the common species. The latter are nocturnal insects, frequenting moist and shady places, and are particularly obnoxious to gar- deners and florists for the injuries they commit to fruits and flowers. They are most partial to the of itself the introduction of a new order. Some of the Coleop- tera (such as Bupestris, Molorchus, &c.) deviate so far, in this respect, from their associates, as to have their wings simply folded longitudinally ; but this is not connected with any other peculiarity which Avould warrant their separation from species to which, in other respects, they are intimately allied. 220 SYSTEMATIC ARRANGEMENT. petals, and many of the most cherished ornaments of the flower border, particularly the stately dahlia, are frequently rendered unseemly by their attacks. The common earwig is widely distributed, and has been found as far north as Boothia. The common names giyen to this insect in Britain are rather peculiar, and it is not easy to say what circumstances have suggested them. Throughout the south of Scotland it is known to the peasantry by the name of coackbell, for what reason I am unable to conjecture. Mr. Newman suggests that earwig, an unmeaning term, may be a corruption of earwing, as the wing is shaped very like the human ear, an ex- planation not unlikely to be the true one. Several anomalies have already been alluded to in the structure of earwigs, and it remains to be added that a very remarkable one also occurs in their eco- nomy. Frisch, De Geer, and many other entomolo- gists have observed the female watching over her eggs with great care, and even covering them with her body as if on purpose to hatch them, a fact whicb is well known to those who are in the habit of overturn- ing stones in search of insects. This is a remarkable contrast to the practice of nearly all other insects, whose maternal duties entirely cease with the depo- sition of the eggs, which they abandon to every hostile influence. The young seem to appreciate and return their mother's aflfection, for they have been seen nestling under their parent like chickens under a hen. It must not be imagined, as some appear to have done, that the incubation alluded to is designed to hatch ORTHOPTERA. 221 the eggs, or could possibly promote their maturation if it were. The temperature of the body of a cold blooded animal is always in equilibrium with the sur- rounding element, and it could, therefore, impart no additional heat to objects subjected to the same in- fluence in this respect as itself. The case is different when multitudes are congregated within a narrow space ; heat is then generated, as is well known to be the case in bee hives. FaM.. BLATTIDiE. The members of this family are very unlike the pre- ceding, and they may be said to differ nearly as much from all the other tribes with which they are asso- ciated. Their bodies are in general broad, oblong, and depressed, the abdomen almost completely covered by the tegmina, which considerably overlap each other on the back, and wholly cover the under wings. The head is curved inwards beneath the prothorax ; the antennae very long, setaceous, and flexible, inserted in a notch in the innerside of the eye ; the two lower joints of the maxillary palpi are somewhat globular, the terminal one (as is likewise the case with the corresponding joint of the labial palpi,) pretty thick and truncated. A conical and articulated appendage projects from each side of the abdomen behind. The legs are thickly armed with spines on the tibia, and all the tarsi consist of five joints. Most of these insects are of a uniform brown colour, ahue well adapted to their habits and the nature of their haunts. A few, which usually frequent flowers, are 222 SYSTEMATIC ARRANGEMENT. spotted and rather more gaily adorned, being, as Stoll affirms, no way contemptible in regard to colouring. They are nocturnal insects, and it was probably one of the species which, on that account, the ancients designated lucifuga. They are exceedingly voracious, scarcely any kind of edible substance coming amiss to them, and even attacking others which can scarcely be said to come under that designation ; of the latter des- cription are leather, silks, and woollen stuffs, which they gnaw with their well armed mandibles, and greatly injure. Their omnivorous and destructive propensities are well known in this country, from the prevalence of one of the species, {B. orientalis,) originally sup- posed to have been brought from the east, and now completely naturalised. It frequents cellars, bake- houses, kitchens, &c. is somewhat less than an inch in length, and of a dark reddish brown colour. The wings are shorter than the abdomen in the male, and merely rudimentary in the female, which, on this ac- count, very much resembles the larva, when these organs are wanting in both sexes. It lays sixteen eggs, which are enclosed in a kind of bag of an oval shape, at first white but afterwards becoming brown. This is borne for a time at the extremity of the anus, and then deposited in some warm place, and secured to the spot by some adhesive gummy matter. Besides the common species about a dozen others occur in Britain, but one-third of these have no claim to be considered indigenous, having been accidentally introduced along with foreign commodities. One of these exotic kinds, however, seems to have obtained ORTHOPTERA. 228 a pretty secure footing in this country, particularly in sea-port towns. This is B, Americana, or kakerlac, a pretty large species with very long antennae, and a yellowish thorax having a brown border and two spots of the same colour on the disk. All the truly indi- genous Blattas are comparatively of small size and seldom or never occur in such profusion as to occasion much injury or annoyance. Even the depredations of the common B. orientalis are insignificant compared with those of foreign lands, where species of more formidable dimensions are sometimes so abundant and obnoxious as to produce no trifling inconvenience to the inhabitants. " The cockroaches/' says Drury in his work on exotic insects, "are another race of pestiferous beings, equally noisome and mischievous to natives or stran- gers, but particularly to collectors. These nasty and voracious insects fly out in the evenings, and commit monstrous depredations ; they plunder and erode all kinds of victuals, dressed and undressed, and damage all sorts of clothing, especially those which are touched ■with powder, pomatum, and similar substances, every thing made of leather, books, paper, and various other articles, which, if they do not destroy, at least they soil, as they frequently deposit a drop of their excrement where they settle, and, some way or other, by that means damage what they cannot devour. They fly into the flame of candles, and sometimes into the dishes; are very fond of ink and of oil, into which they are apt to fall and perish. In this case they soon become most oflbnsively putrid, so that a man might as*well sit over 224 SYSTEMATIC ARRANGEMENT. the cadaverous body of a large animal, as write with the ink in which they have died. They often fly into persons' faces or bosoms, and, their legs being armed with long spines, the pricking excites a sudden horror not easily described. In old houses they swarm by myriads, making every part filthy beyond description wherever they harbour, which, in the day time, is in dark corners, behind all sorts of clothes, in trunks, boxes, and, in short, every place where they can lie concealed. In old timber and deal houses, when the family are retired at night to sleep, this insect, among other disagreeable properties, has the power of making a noise which very much resembles a pretty smart knocking with the knuckles upon the wainscotting. The Blatta gigantea of Linnaeus in the West Indies^ are, therefore, frequently known by the name of drummers; three or four of these noisy creatures will sometimes be impelled to answer one another, and cause such a drumming noise that none but those who are very good sleepers can rest for them. What is most disagreeable, those who have not gauze cur- tains are sometimes attacked by them in their sleep. The sick and dying have their extremities attacked, and the ends of the toes and fingers of the dead are frequently stripped of both skin and flesh." * The species to which the above account principally refers has been figured on the adjoining plate as a conspicuous and characteristic example of its tribe. * Drury's lUustrations of Exotic Entom. Westwood's Edit, vol. II. 70. ' 225 BLATTA {BLABERUS) GIGANTEA. Plate VII. Fig. 1. Blatta gigantea Linn. Fahr Blaberus giganteus, Serville Drurifs Exotic Insects^ vol. ii. PI. 36, fig. 2. This is certainly the largest species of this family ; the length of the body being frequently about three inches, and the wings when expanded often measur- ing half a foot from tip to tip. The general colour is a dusky livid j head reddish-brown ; antennse half the length of the body, and of a brown colour. The thorax, which is thin and flat, of comparatively small size, and of a transverse oval shape, has a large quadrate brownish-black spot in the centre. The tegmina, as well as the wings, are livid, the former appearing striated, and having a narrow brown streak on each, extending from the shoulder along the mid- dle. Abdomen brown ; the legs reddish-browoi. This species is a native of South America and the West Indian Islands. It has occasionally appeared in this country in the vicinity of harbours and docks, but can no more be regarded as a native than the bird-spider of America {Mi/gale avicularia), and other foreign visitors, which are sometimes found in such situations. This insect well represents the general form and appearance of the Blattae, but there is a small section of somewhat dissimilar aspect aris- ing from the back being rather convex, the colours deeper and more varied, with other less obvious dif- ferences. As an example of this modification of form, we have figured p 22G SYSTEMATIC ARRANGEMENT. B. PETIVERIANA. Plate VII. Fig. 2. Linn. Fair. — Blatta heteroclita, Pallas, Spec. Zool. — StolVs Blattes, PI. 5. d. figs. 21, 22 Cimici affinis iiiger Petiv. C?a«op. P1.71,lfig. 1. It is about ten or eleven lines in length, and of a dull black colour ; antennae about half the length of the body. The tegmina, when closed,, overlap each other, and the upper one has four large spots of yel- lowish white, three placed longitudinally along the exterior border, the fourth smaller, and situate near the middle of the inner margin. The other wing case has only the three exterior spots, the central portion of the inner margin being of a fine reddish- yellow. The wings are very short, and seem scar- cely fitted for flight. The abdomen above is rather wider than long; the colour black, with a small triangular falvous spot at the side of each segment, and two small lateral appendages behind. Under- side and legs black. This insect, which is a native of the West Indies, was first figured by Petiver, one of our oldest Bri- tish Naturalists^ after whom it has been named. Fam. Mantid^. This curious and interesting group will be easily recognised by the following summary of its most characteristic features. The head is long, triangular, and vertical, furnished with large eyes, (sometimes having a triangular prolongation in front,) and three MANTIDiE. 227 distinct stemmata ; antennae long, filiform, and slender, composed of numerous joints, sometimes pectinated in the males ; terminal joint of the palpi ending in a point ; ligula quadrifid ; tegmina thin and reticulated, usually covering the wings, legs un- equal, the anterior pair elongated, thickened, and armed with teeth ; tarsi five-jointed. This tribe includes a variety of very singular forms, which have received the name of walking leaves, from their resemblance in colour, form, and texture to these parts of vegetables. The veined and reticulated tegmina may even be said to represent the difi*erent states of leaves ; in some appearing but partially developed, and in others assuming the variety of tints which characterise the different sea- sons. Thus they are in some fresh and green, and this, as in the foliage of plants, is the prevailing hue ; in others they appear brown or rust-coloured, with the surface wrinkled and shrivelled, strongly resemb- ling withered or decaying leaves. The likeness is frequently heightened by the foliaceous expansions of the legs, while the long narrow shape of these members, and also of the thorax and abdomen, as- similate them, in some measure, to twigs, footstalks, or small branches. These insects are carnivorous, a disposition which might be inferred from the prominence of their eyes, size and shape of the mandibles, and their being fitted for rapid motion. They prey upon weaker individuals of their own class, and like most other insects of pi-edatory habits, have a peculiar provision 228 SYSTEMATIC AKRANGEMENT. for enabling them to secure their victims. One of the distinguishing marks of the present family is the great length and thickness of the forelegs, which, o\ying to the length of the thorax, usually appear remote from the other pairs, and placed near the head. They thus admit of being extended forwards a considerable way from the bodj% and their struc- ture admirably adapts them for seizing small objects, The thigh, which is the thickest portion, is grooved on its inner edge, and beset with a double row of strong spines ; the tibia is so formed as to close upon it as the blade of a pocket-knife does upon its handle, and being likewise spinous on its interior edge, effectually secures any object that may be within, in a manner somewhat similar to what is practised by that carnivorous vegetable the Dio7iea muscipula. The efficiency of this implement is shewn not only in seizing small insects, which be- come an easy prey, but in the combats which the Mantidae carry on with each other, for a dexterous application of it decapitates an opponent as expe- ditiously as could be done by a guillotine. In a leg so constructed, the tarsus becomes a very subordin- ate appendage, being short and weak, and apparently unequal to suppoit the body, resembling that part in certain Coleopterous genera (such as Phanceiis, Geotrupes, &:c.) where it shews a tendency to be- come obsolete, as its functions are performed by the extremity of the tibiae. These raptorial legs are often equal to the entire length of the body, and in some instances even surpass these dimensions. MANTID^. 229 They are usually borne extended before the insect, and frequently raised upwards, and clasped as it were together. This attitude led the ignorant to the fantastical notion that these insects can divine or indi- cate future events, and in many places they are re- garded with a kind of religious veneration. The species which occurs most plentifully in the southern provinces of France {M. religiosa), is particularly famous for pointing out the road to children and others who happen to have lost their way. " Puero interro- ganti," says the credulous Rondelet, " de via altero pede extento rectam monstrat,a^yz, maxillary palpus, — Fig. 23, lower lip ; — a, fulcnun ; m n^ mentum ; I 2, labium ; I jo, labial palpi. The variations of the antennae are too numerous to he specified in this place. The number of joints is from three (their amount in Hyloioma) to about fifty. These multiarticulate antennae are chiefly to be found among the Ichneumonidse, whose economy renders it necessary that they should be very flexible for the purpose of exploring the holes and crevices into which they introduce their eggs. In some instances the antennae are bipectinated ; in other cases (as in Cryptus) they appear double, the third joint being long and furcate. They are often very dissimilar in OF INSECTS. 299 the two sexes. In the genus just named, for ex- ample, the male antennae are quite simple, and filiform, while the female exhibits the remarkable peculiarity just alluded to. The prothorax is usually small in hymenopterous insects, but in many cases it is quite distinct, while in the Chalcididse, Uroceridse, &c. it forms a con- siderable portion of the dorsal area. The latter, however, generally consists of the mesothorax, which is here greatly enlarged, in order to afford sufficient momentum to the fore wings, on which the power of flight, in this order, chiefly depends. It is there- fore this section of the thorax, which, in descriptive language, is spoken of simply as the thorax. The metathorax is proportionably diminished, but still holds sufficient prominence to correspond with the importance of the hinder wings, which are also es- sential to flight; and it seems to become enlarged as the size of the hinder wings increases. The structure of the wings, and the arrangement of the nervures, have been perhaps more carefully studied in this than in any of the other orders, partly in consequence of their having been made the basis of a systematic classification of the genera. Taken in connection with characters derived from other parts, they must be admitted to afford valuable marks of distinction, both among the Hymenoptera and Diptera. It is, therefore, important, that the designations of the nervures and the cells formed by their intersection should be explained. When the nervures of the upper wings exist in their maxi- 300 SYSTEMATIC ARRANGEMENT mum state of development, they are five in number. The longitudinal one placed along the anterior border of the wing, is usually called the costal nervure : it was named by Jurine, who first gave a nomenclature to these parts, the radius, from a notion that it was analogous to the bone so named in vertebrate animals. For the most part this is the strongest nervure in the wing, as it forms the ante- rior edge when that organ is extended, and has, therefore, to cut through the air during flight. The nervure next to this, and running parallel with it, is the sub- costal nervure, — the cubitus of Jurine. Both these terminate in an opaque expansion on the anterior border of the wing not far from the middle, which is called the stigma, a term which has been appropriated to a totally different part of structure, but is now in too general use in its twofold sense to be disturbed. The sub-costal gives oiT, a little before its origiii, a third nervure, which runs almost in a direct line towards the centre of the wing, and, at a longer or shorter distance from its commence- ment, describes numerous zigzag lines; this it has been proposed to call the medial nervure. Beyond this a pretty wide area usually intervenes, which is bounded posteriorly by a nervure running somewhat obliquely towards the centre of the hinder border, which has received the name of sub-medial. The last is more slender than the rest, and has been very appropriately called the anal nervure. The nervures just described are always more or less united by transverse and recurrent nervures. OF INSECTS. 301 enclosing small cells which derive their names from the adjacent nervures. Thus the space or cell, situate between the costal and sub-costal nervures, is called the costal cell ; that bounded by the sub- costal and medial nervures, the medial cell ; and so on. On attending to the smaller nervures which usually occupy the exterior half of the wing, we will per- ceive one taking its origin from the stigma or from the extremity of the sub-costal nervure, and running towards the apex of the wing. This is named the radial, and the space between it and the anterior margin, the radial cell. The latter is commonly divided into two by a secondary nervure, in which case there are said to be two radial cells. The ex- terior of these is said to be appendaged, when the recurrent nervure springs not from the stigma but from the external margin of the wing. A second nervure, named the cubital, springing from the extremity of the sub-costal nervure, or the recurrent branch which unites the latter to the medial, is directed like the former to the extremity of the wing, which it usually reaches a little below the apex. The enclosed space is divided by cross nervures into cells, which are named cubital cells. Between the nervure so named and the sub- medial, a considerable space likewise exists, which is also divided by intersecting nervures. The cells thus formed Latreille has proposed to call dis- coidal. Two cells may be observed in the space 302 SYSTEMATIC ARRANGEMENT comprised between the sub-medial nervure and the posterior margin of the "vving, which are denomi- nated the posterior cells. '^Such is/' says Lacordaire, of whose accurate summary we have occasionally availed ourselves in the preceding description ; '' such is, with a few- modifications relating rather to the form and size of the cells than their number, the reticulation of the wings of the Hymenoptera, composing the genera Tenthredo, Cimbex, Allantus, Urocerus, Sirex, &c. On examining the series of genera to the opposite limits of the order, we perceive changes introduced more or less important in proportion as we recede from the groups just named. Even among the Evanii, which are very nearly allied to them, we observe only four principal nervures, and the cubital and discoidal cells are each of them reduced to one. In almost all the genera which follow, the nervures, instead of extending to the edge of the wings, terminate in the middle of the surface. If the cells are closed they retain their usual form ; but if, as often happens, they are not united by trans- verse nervures, they remain open, and are then said to be incomplete. It likewise happens occasionally, that a cell at its base does not occupy the same space as that which precedes it, and is united to the latter by a kind of stalk more or less elongated ; the cell so circumstanced is said to be petiolated. Following these degradations we see the cells gradually dis- appear by turns, till we come to Psilus, in which OP INSECTS. 303 there is no trace of them, except in the costal alone, which loses itself in a scarcely perceptible stigma."* The value of the generic characters afforded by the modifications which the figure of the cells under- goes, may be inferred from the fact stated by M. Jurine, that he could, in most cases, determine the genus of a hymenopterous insect from the inspec- tion of the wings alone. As among the Hemiptera, the inferior wings are more or less closely united to the superior when in action, but this is effected by a different kind of mechanism. Along the anterior edge of the secon- dary Avings is placed a series of very fine hooks, {hamuli,) which attach themselves to the hinder margin of the primary pair, and a continuous sur- face of some extent is thus presented to the air. From the preceding details it may be inferred that the Hymenoptera possess great powers of flight. It is in fact one of the orders in which that power has reached its maximum; all the necessary con- ditions being found united. The great distances to which bees fly in search of honey, often against a strong wind, are well known ; and even when they are loaded with pollen, or other substances — with " treasures suckedfrom buds and bells" — the rapidity of their aerial movements appears in no degree re- tarded. The humming noise which many of them emit is not produced by any organs specially formed for that purj^ose, as among the Hemiptera and Orthoptera, * Intro, h. rEntom. I. 368. S04 SYSTEMATIC ARRANGEMENT which are the only tribes so endowed. It is occa- sioned simply by the forcible expulsion of the air from the thoracic spiracles. It was long thought to be caused by the vibration of the wings ; at other times it was attributed to the friction of the base of these organs against the hard sides of the thorax. But both these opinions are disproved by the fact, that the sound can be produced in certain cases when the wings are entirely removed. Although it has not its source in these organs, it is obvious, how- ever, that it is materially modified by them. This can easily be proved by cutting off a portion from the extremity of the wings, when the sound will become weal^er and more shrill, and it decreases in- sensibly as the mutilation is carried downwards to the base. If the portion of the latter inserted into the thorax be completely removed, the sound in general . will no longer be produced. The secondary part which the wings thus take in its production, becomes apparent when we reflect on the manner in which respiration is performed among insects. The air is forcibly expressed from the thoracic spiracles only when the muscles of the thorax are in strong action ; when the insect is in repose or merely using its legs, these spiracles take scarcely any part in the office of respiration, and, consequently, are incapable of producing sound. No sooner, however, are the wings brought into action than they cause the play of the numerous powerful muscles with which the thorax is filled ; their contractions and movements compress the trachea in all directions, and the air OF INSECTS. 305 is necessarily forced through the only openings which present themselves. The more rapid the flight, the greater must be the muscular action, and, conse- quently, the expulsion of the air more violent; conditions which perfectly accord with the various degrees of intensity observed in the sounds emitted in different states of movement. When a portion of the wing is cut off, the rapidity of flight is neces- sarily diminished, and the muscles contract but feebly^ in consequence of the lever which moved them being shortened. If the lever be completely taken away, which cannot be done without the laceration of some of the muscles, the contracting power cannot be exercised with sufficient force to eject the air, or, in other words, produce sound. In accordance with this view, the sound is found to be immediately stopped, if the apertures of the spiracles be filled up with gum or any other ad- hesive substance, and cannot of course be produced in v/hatever state the wings may be. The abdomen in hymenopterous insects is often very small, and in some extensive tribes it is at- tached to the thorax by a very slender segment forming a kind of foot-stalk. The most remarkable appendage connected with it is the ovipositor, which, in most tribes, is very much developed. This in- strument assumes a great variety of forms in diffe- rent families to adapt it to their diversified economy ; and, in all, exhibits a beautiful example of mecha- nical contrivance. The members of this interesting order usually u 306 SYSTEMATIC ARRANGEMENT live, in their perfect state, on flowers ; some of them subsisting on honey and the juices of fruits, while others are carnivorous. The larvae are very diversi- fied both in their habits and structure. These insects are very numerous and widely distri- buted. In amount of species they are probably next to the Coleoptera and Diptera; and as the societies many of them form are exceedingly popu- lous, the number of individuals must be very great. Considerably above 2000 have been described as British, but as many of the parasitical kinds are very minute, it is likely that no small number re- main undetected. Latreille divides the order into two great sections. I. Terebrantia, in which the females are provided with a saw-like ovipositor. This he divides into two subsections: — 1st, Securifera; having the ab- domen sessile and provided with a saw; larvae with feet. Fam. Tenthredinidm, Siricidce, Id, Fupi- vora ; abdomen pedunculated and provided with a borer; larvae without feet. Fam. Evaniida?, Ich- neumonidce, Cynipidce, Chalcididce, I^roctotrujndce, Chrysididoe. Section II. Aculeata ; abdomen of the females armed with a sting. This includes four subsections. \st, Heterogyna ; females or neuters wingless. Fam. Formicidce, MutilUdce. 2d, FoS" sores ; females winged, wings not folded, basal joint of posterior tarsi simple. Fam. Sphegidae, ^c. Sfc. 3d, Diploptera ; females and neuters winged, wings folded. Fam. Vespidce, S^^c. Uh, Mellifera ; females and neuters winged, wings not folded, posterior tarsi OP INSECTS. 307 with the basal joint much dilated. Fam. Andrenidce, Apidce. In illustrating this order more in detail, we shall first select a characteristic example from the family of the Tenthredinidse.* Fam. Tenthredinid^. This extensive family may be known by having the abdomen sessile, or united by its whole breadth to the hinder part of the thorax, in such a manner, that it possesses but little power of separate move- ment. The maxillary palpi are always six-jointed ; the labial four-jointed ; labium trifid ; wings ample, and provided with many complete cells j females with an ovipositor. It is from the use and appearance of the instru- ment just named that these insects are called saw- flies. It is placed at the extremity of the abdomen of the female on the under side, and is so con- structed, that it combines the properties of a saw and auger. It consists of two plates of the same form and size as two external valves, which serve as a sheath to them, and enclose a short triangular * We purposely exclude from these illustrations the most interesting of all the hymenopterous families, the Apidce^ as their history has already been given in a way commensurate with its importance, in a separate volume. The details there afforded of this characteristic group are so ample, as to pre- clude the necessity of entering at such length into the gene- ralities of the order in the above sketch as it would other- wise have been nece*ary to do. 308 SYSTEMATIC ARRANGEMENT appendage at tlieir base. The lower edge of each of these plates is finely toothed throughout its whole extent, the teeth directed backwards, and at the same time turned a little outwards. The surface of these plates is very smooth internally, but the outer side is partly covered with very closely placed oblique striae and elevated lines. When the in- strument is put in motion on the surface of a leaf, or on a twig, the small teeth act as a saw, while the lateral ridges perform the office of a file or rasp. By this means a suitable opening is soon formed for receiving the eggs. These are sometimes placed within the woody substance of the branches of shrubs, but more commonly they are attached to the leaves. An instance of the former sort is ob- served in the Rose Saw-fly, {Hylotoma Uosce,) and a familiar example of the latter in the species which infests gooseberry and currant bushes, w'hich ar- ranges its eggs in rows along the mid rib and principal nervures of the leaves. In all cases the eggs are not long in being hatched ; and the young larvae generally find their appropriate food in the leaves of the plant on which the provident mother had placed them. From the general resenii, lance these larvae bear to the caterpillars of butterflies and moths, they are cSiWeA false caterpillars, as the word caterpillar ought to be restricted to the former. A very slight ex- amination is sufficient to enable one to discover de- cided marks of distinction between them. The true caterpillars — the larvae of Lepidoptera — have never OF INSECTS. 309 more than sixteen feet, while the larvae of saw-flies have generally from eighteen to twenty-two; a few have only six, a circumstance which again distin- guishes them from true caterpillars, in which the number of these parts is never below ten. Another mark of distinction is affbrded by the structure of the feet. In lepidopterous larvae the abdominal legs are surmounted by a coronet of small hooks, ap- pendages "wdiich are never found in those of false caterpillars, as the latter are simply mammiform protuberances. This minute difference, which can only be detected by the microscope, has however a material influence over the habits of the respec- tive caterpillars, which often enables us to distin- guish them at first sight. The coronet of hooks converts the membranous or abdominal legs of true caterpillars into efficient instruments of prehension, and they accordingly fix their body by means of them to the plane of position, while the head and anterior part remain free. The abdominal legs of the others, on the contrary, are mere points of sup- port, incapable of clinging to an object, and the larva consequently fixes itself by its pectoral or forelegs, which are much developed for the purpose. The whole of the abdominal portion of the body is thus left at liberty, and it is either borne curved inwards, (as in the gooseberry saw-fly,) or projects into the air in variously contorted and singular postures, as is remarkably exemplified in the wil- low saw-fly, (Nematus Caprece,) and the larva of Hylotoma Rosse, which has the extremity of its 310 SYSTEMATIC ARRANGEMENT body almost always elevated and curved in the form of the letter S. Additional distinctive characters might he mentioned, such as the form of the eyes, which are pretty large in pseudo-caterpillars, and placed one on each side of the head, while in true caterpillars they are small almost invisible points disposed in a circle ; but those already referred to will suffice to distinguish the two tribes. The body of pseudo-caterpillars is generally com- posed of twelve segments, but the incisures are in- distinctly defined, and liable to be confounded with the transverse wrinkles which thickly cover the whole surface. Many of them are marked with bright and varied colours, but the majority are of one colour. In this respect they often undergo a remarkable change after they have cast their last skin, the colour becoming entirely unlike what it was before, so that it is impossible to recognise the same individual. This change, indeed, extends even farther than to colour, for such kinds as are furnished with tubercles or spines in their earlier stage, lose them at their last moult and become smooth ; that of the gooseberry species, for example, loses the black tubercles which made the surface appear as if shagreened. Like the flies they produce, these larvse are sluggish and inactive, seldom moving from the place where they have fixed themselves, unless when requiring an additional supply of food. When not engaged in feeding, or when apprehensive of danger, tliey roll themselves into a circle, sometimes with the tail elevated in the centre. The greater OF INSECTS. 31 1 number live exposed on the foliage of plants, but others take up their abode in the interior of slender shoots and feed upon the immature pith; others lodge in the interior of fruits and cause them speedily to decay. The first insect selected as an example of the family of saw-flies, is named CIMBEX DECEM-MACULATA. Plate XXX. Fig. 2. Leach Zool. Mis. Ill, p. 106— Curtis" Brit. Ent. L PL 41. The genus cimbex possesses six-jointed antennse, of which the second joint is much the longest, and the terminal one oblong and club-shaped. The two terminal joints of the maxillary palpi are small and ovate ; the labial palpi scarcely longer than the labium ; labrum small and oblong ; mandibles large and acute, the inner side irregularly toothed ; hinder thighs very thick in the males ; the tibise terminated by a pair of obtuse spm's, and the tarsal joints pro- duced into a spine beneath. The larvae of Cimbex have twenty- two feet ; and some of them, when annoyed, are capable of squirt- ing a greenish liquid from two lateral apertures. When about to enter the pupa state, they form an oblong hard case, which is usually attached to the tree or shrub on which they fed. We have seven or eight British species, of which the above is one of the rarest. The body is black, the abdomen tinged with violet, the third and seventh segments 312 SYSTEMATIC ARRANGEMENT with a greenish-yellow spot on each side, the three intermediate joints of the same colour with violet- black in the centre ; antennae and tarsi testaceous ; wings pale fulyous. ATHALIA CENTIFOLI^. Plate XXX. Fig. 3. Fig. 4, Caterpillar. This is the Turnip saw-fly, which has occasioned so much loss to agriculturists within the last few years. It is about four lines in length, the figure on PI. XXX. being considerably magnified in order to show the parts more distinctly. The general colour is bright orange yellow; antennae and head black, the underside of the former dull yellow; palpi yellow ; thorax black, the collar, a triangular spot in front and sometimes one behind, reddish- orange ; abdomen and legs reddish-yellow, the tips of all the tarsal joints and of the tibiae black ; wings yellowish at the base, the costa and stigma dark- brown. The caterpillar, (PI. XXX. fig. 4,) has six pectoral, fourteen abdominal, and two anal feet. It is of a dull slate or greyish-black colour, with a somewhat lighter line along the sides just above the feet. It is known in different parts of the country by the names of black palmer, black canker, black slug or caterjnllar, negro or nigger. Full descriptions and history of this insect, which it is desirable should be well known in order that some remedy may be devised against its depredations, will be found in Mr. Yarrell's paper in the second OF INSECTS. 313 volume of Transactions of the Zoological Society, Mr. Newport's Essay, Curtis' Brit. Ent. fol. 617, and in the Quarterly Journal of Agriculture. SIREX GIGAS. Plate XXXI. Fig. 1. S. gigas, Linn. fem. ; Donov. vi. PI. 197, fern. S. marisca, Linn. Male. The structure of the oral organs in this genus has been minutely delineated on PI. XXVI. The group is a very distinct one, and contains about half a dozen of very conspicuous British species. S. gigas is rare, but is found occasionally in the more southern counties of England, generally frequenting pine woods. The abdomen of the male is yellow, with the hinder ex- tremity black ; the female black, Avith the second and three last segments of the abdomen yellow. The larvae live in trees, to which they sometimes prove very injurious. TREMEX COLUMBA. Plate XXXI. Fig. 2. Sirex columba, Liiiti, S. Pensylvaniciis, De Geer^ Mem. iii. PI. 30, fig. 13. West. 'Drury, PI. 30, fig. 2. This species affords an example of the Siricidae of the New World, it being a native of the country round New York and other parts of North America. The head and thorax are brown orange ; abdomen cylindrical, black, with five broad yellow bands, the hinder one interrupted ; apex of the abdomen like- wise tipped with yellow ; legs orange brown. 314 SYSTEMATIC ARRANGEMENT JOPPA PICTA. Plate XXXI. Fig. 3. This and the species delineated on the following plate, afford examples of tlie very extensive family of the Ichneumonida^j, whose economy is so remark- able. They deposit their eggs in the bodies of other insects, particularly caterpillars, which are there hatched, and the young feed on the entrails of the unfortunate victim. To enable them to convey their eggs into holes and fissures where caterpillars or pupae often lurk, they are generally provided with a long ovipositor, which is usually very slender, and too weak to pierce the skin of the hand, although the insects often make the attempt when seized. As this weapon generally appears tripartite, these insects were formerly named Muscoe tripiles, and, from their habit of vibrating their antennae, Muscce vibrantes. They may, in general, be known by their narrow elongated form, attenuated, and, in most cases, petiolated abdomen, with its hair-like appen- dages behind, and long many-jointed antennae, which are often recurved and annulated. The Ichneumonidae are a very numerous tribe, no fewer than 1300 European species having been described by Graven- horst in his monograph of this family, and of these a large proportion occur in Britain. Our British species, however, have not yet been carefully inves- tigated, and it is much to be desired that some com- petent observer would undertake the task. These insects perform an essential service by destroying so OF INSECTS. 315 many caterpillars^ which, if left to multiply unchecked, would totally consume many of our most useful plants. The genus Joppa is principally distinguished hy the form of the antennae, which are much thickened heyond the middle, and then terminate in a point, as is well seen in the handsome species (J. Joppa,) figured on PI. XXXI. Another example of this genus is given on PL XXVI. fig. 24, J. aniennata, (Fabr. Syst. Piez. 122, Ent. Syst. 158, Ichneumonia,) from a drawing hy Mr, Westwood. It is a native of South America. The specimen is in Mr. Hope's collection. EPHIALTES MANIFESTATOR. Plate XXXII. Fig. 1. Ctrav. Pimpla manifestator, Fabr. Syst. Piez. Ichneumon mani- festator, Linn. Marsham in Linn. Tra7is. HI. 23, PI. 4, fig. 1-5. The subgenus ephialtes of Gravenhorst is charac- terised by a long abdomen, which is generally tuber- culated, the anterior segments longer than broad, those at the apex with a longitudinal groove on the underside in the females; ovipositor long. The species above named is from eleven to fifteen lines in length, the female being largest. Body black, palpi and labrum ferruginous, thorax sometimes with a ferruginous spot at the base of the Mangs, the latter light smoke colour; legs long and rather slender, fulvous or rufous, the posterior tarsi and tibiae, and sometimes the knees, fuscous. Ovipositor longer than the body, the tube chestnut red. 31 G SYSTEMATIC ARRAXGEMENT Perhaps the largest of the European Ichneumonidse, and met with occasionally in most parts of Britain. STEPHANUS CORONATUS. Plate XXXII. Fig. 2. Jurine''s Hymenop. PI. 4, genus 4. In this group tlie head approaches to a glohular form^ the mandibles terminate in an entire or slightly notched point ; the thorax is narrowed and elongated in front, and the abdomen appears almost sessile. The antennae are long and slender_, consisting of 32 joints. The species named coi'onatus is black, the abdomen dark red ; legs likewise red, the tarsi and and anterior tibiae pale. The insect is usually found, according to Jurine, on dry wood, and, when it flies, the abdomen forms a right angle with the thorax. PELICINUS POLITURATOR. Plate XXXII. Fig. 3. Driiry's Exotic Ins. Vol. II. PI. 40, fig. 4. This generic group is at once known by the singular appearance of the abdomen, which is very long, nearly filiform, arched, and inserted in the thorax a little above the origin of the posterior legs. The hinder legs are thickened, and the antennae straight and extremely slender. The species above referred to is entirely black, the wings tinged with brownish yellow. It is a native of Jamaica. It is probable that the very long and slender abdomen serves, in these insects, the same purpose which a lengthened ovipositor does in others, enabling them to place OF INSECTS. 317 their eggs in the bottom of holes and fissures, in the bark of trees, &c. which they might not other- wise be capable of reaching. Order VII. — Lepidoptera. This order includes the well known tribes of butter- flies, hawk-mothsj and moths properly so called, all of which possess the common property of having the wings, which are four in number, covered with small scales or feather-like bodies. It is to this the name refers, being derived from Xscrr/g, a scale. No kind of insects are more dissimilar in their diflferent stages of metamorphosis. When they issue from the egg they appear in the familiar form of caterpillars, these change into a chrysalis, from which the perfect butterfly is in due time produced. Unfortunately we do not yet possess a complete systematic arrange- ment and description of these insects, at least not one conformable to the most recent and approved method of classification. This is the case in par- ticular with the nocturnal Lepidoptera or moths, many of which are still undescribed. Our native species, however, of which there are nearly 2000, have been well described by Stephens in his Illus- trations of British Entomology, by Haworth in his Lepidoptera Britannica, and in several other works. Among the best works on exotic Lepidoptera may be mentioned Horsfield's Lepidoptera Javanica, Boisduval's Species General des Lepidopteres, (Paris, 318 SYSTEMATIC ARRANGEMENT 1836,) and Godart's elaborate articles in the En- cyclopedic Methodique. It is not intended to enter into the general history of the Lepidopterous order in this place, because three volumes of our entomological series have al- ready been occupied with it, and it is not desirable to encroach further on the space requisite for the elucidation of the orders we have not touched upon elsewhere. It is contemplated, moreover, to add another volume relating to this order, comprehend- ing the history of exotic moths and hawk-moths, w^hich will afford an opportunity of supplying what it may be further thought requisite to say on the subject. Order VIII. — Strepsiptera. This singular order, composed of a few minute para- sitical species, was established by Kirby, and it cor- responds to what has since been named Rhipiptera by Latreille, and Rhipidoptera by Lamarck. The insects are extremely anomalous, insomuch that Lat- reille, on examining one of them, exclaims, " animal prorsus singulare, animum excrucians ! " It is diffi- cult to trace their natural affinities, from the imper- fect structure of the mouth, and a greater number must be examined with anatomical precision, before we can be certain with regard to the position they ought to occupy in the series. In the synoptical table on page 200, it is stated that they have two wingSj and this character, in connexion with the form OF INSECTS. 319 of the mouthy will be sufficient to distinguish them. But it has been recently shown, that two minute appendages, attached to the sides of the mesothorax, may be regarded as representing anterior wings ; these have been named pseudelytra, or prebalanciers. The structure of the other parts will be well under- stood from the dissections on PI. XXXIII. which we have taken the liberty to copy from Mr. Curtis' Brit. Ent. as they are the most satisfactory that have come under our observation. The head (E) is broad and sessile, with a triangular projection in the centre ; eyes lateral, globose, and formed of few large facets ; antennae, with more than one branch (F 1, and G) ; palpi (H) large and two-jointed. The prothorax and mesothorax (I and K) are very short, being narrower than the head ; the mesothorax (D G), on the contrarj'-, is large and long, and produces a large scutellum (D*), which projects over the abdomen, the latter composed of 8 or 9 joints, and somewhat incurved at the extremity. In Stylops the anterior wings appear as represented at K 9. It is on ac- count of their twisted appearance that the name Strepsiptera (from (^r^e-^tg and crrsgov) has been ap- plied. The hinder wings, or what may be regarded as the only wings, if we consider their function, are very ample, folded longitudinally like a fan, the ner- vures remarkably fine (L 10). The legs are short and compressed, without spines, the tarsi (which are four-jointed,) having each joint furnished with a- pubescent membrane (K 8*), claws wanting. Rossi was the first who observed one of these 320 SYSTEMATIC ARRANGEMENT singular insects, and he concluded that they belong to the hymenopterous order. This he was induced to do chiefly by the circumstance of their being para- sitic, in the larva state, on the bodies of various kinds of bees and wasps {Andrenidce and Vespidce). The larva and pupa of Stylops are figured at B and C, PI. XXXIII. They live between the abdominal segments of the bee, as represented in fig. A, a b. An interesting account of the discovery of an English species of this order will be found in Kirby's IMono- graphia Apum Angliae, II. 113, and a full description of the order, in his Memoir in the XI. volume of the Linnaean Transactions. As at present known, the order may be regarded as comprehending four genera. These may be dis- tinguished by the antennae : Halictophagus has four branches in these organs, in all the rest only two exist. In Xenos the antennae are inarticulate ; in Sfi/lops the outer branch is flattened and three-jointed, this is likewise the case with Elenchus, but the joints are very long and slender. STYLOPS DALII. Plate XXXIII. Fig. 1. Curtis' Brit. Ent. Vol. v. fol. 226. Body of a deep velvet black. Scutellum at the base, and abdomen at the sides, ochre yellow ; wings white and iridescent ; legs brownish. Length about a line and a half. Obtained from Andrena barbilabris by Mr. Dale, after whom the insect is named. OP INSECTS. 321 XENOS PECKII. Plate XXXIII. Fig. 2. Linn. Trans. Vol. xi, PI. 8, fig. 8. Body brownish black ; antennse pale fuscous, almost diaphanouSj sprinkled with minute white points. Wings ashy white, the anterior margin and nervures deep black, legs dull cinereous, tarsi dusky, extremity of the abdomen pale reddish. Length 1| lines. Larva and pupa found in Polistes fucata, an Ame- rican insect. Order IX. — Diptera. This extensive order admits of a very brief and precise definition. The possession of only a pair of mem- branous wings, and a mouth formed for sucking, aifords obvious characters for distinguishing it from all others. It is to the former peculiarity that the name refers, being derived from big, twice, with the usual addition. Another marked singularity is to be found in the presence of two clubbed moveable bodies, termed balancers or halteres, projecting from each side of the thorax, and placed a little behind the wings. The sucker attached to the mouth is composed of several slender pieces, from two to six in number, which are enclosed in, or rest upon, a fleshy pro- boscis or sheath, which gives support to them when employed, and also serves to pierce the cuticle of plants or animals, on the juice of which the insects live. When these pieces are six in number, they X 322 SYSTEMATIC ARRANGEMENT are found to correspond in position and function, however different they may be in form, to the parts of the mouth in mandibulated insects, and much ingenuity has been exercised by entomologists in tracing this connexion. All these parts are fully developed in the mouth of Tabanus, and vi^ill be seen by the annexed figure, in which a represents the palpi, b the la- . brum, c the mandibles, d the maxillae, e the tongue, and g the labium. The latter is usu- ally very large and fleshy. Many 1^^^^ ^ of the parts just mentioned, how- ^'^•Ow'^ ever, disappear in certain dipte- reus tribes, and in some {(Estri- dee,) all of them are completely obliterated. The antennae are sometimes long and conspicuous, bearing no inconsiderable resemblance, as is remarked by LatreJlle, both in form and appendages, to those of the nocturnal Lepidoptera. In an extensive sec- tion of the order, again, they are very short, com- posed of only two or three joints, the terminal one of which is commonly spindle-shaped, lenticular, or prismatic, with a simple or plumose bristle springing from its upper side. The eyes are lateral, commonly large, those of the males being much the largest, and frequently meeting, or nearly so, on the crown of the head. The facets are sometimes larger on the upper than on the under side of the eye. They are occasionally variegated with bands of brilliant colours. When OF INSECTS. 323 ocelli are present, vvhicli is very frequently the case, they are usually three in number, and placed on the vertex. The mesothorax is the segment of the anterior part of the body most developed in these insects, and it is so to such an extent as to leave but little space for the others, the prothorax being, in some cases, almost evanescent. The wings are somewhat long, and in general rather narrow, commonly clear and transparent, with simple nervures disappearing before reaching the apex, and crossed by a few transverse ones, the neuration being greatly more simple than in the hymenoptera. At the base of the wing, we very frequently find two rounded membranous scales applied with their faces to each other, which are named wing- scales, alulets, or winglets. They are sometimes of considerable size, and doubtless aid the movements of the wings materially in the act of flying. The use of the halteres, which have been already alluded to as two slender clubbed bodies placed be- hind the wings, can scarcely be said to be accurately known, but it is conjectured that they assist in giving a proper poise to the body in flight. Some have likewise supposed them to be connected with the function of respiration. They are often of a pale colour, and, when the winglets are large, partially covered by these appendages. The abdomen is attached to the thorax only by a small portion of its transverse diameter ; it is often long and narrow, sometimes oval or nearly round, varying in the number of its segments from five to 324 SYSTEMATIC ARRANGEMENT nine. In the females it frequently terminates in a tubular ovipositor^ the joints of which are retractile within each other. The legs are generally long and slender, the articulations of the tarsi always five in number. The terminal joint, or that which bears the claws, is often provided with two or three mem- branous lobes, by the aid of which the fly is enabled to walk on glass and other smooth surfaces against gravity. This it was long supposed to do by the pressure of the atmosphere, the lobes in question acting as suckers and forming a vacuum. It has been recently conjectured, however, in opposition to this view, that it is accomplished by means of a glu- tinous secretion. The larvae of dipterous insects are in some respects even more peculiar than the mature fly. They are generally of a conical shape, the head being the nar- rowest part, and in all cases destitute of feet. The head is small, retractile, and variable in form even in the same individual, — that is to say, it is composed of a comparative soft fleshy substance which the in- sect can modify in shape at pleasure, to answer its various purposes. The colour is generally pale, but sometimes it is dark, and even bright red. The stig- mata, in the species not aquatic, are most commonly placed in a cavity in the hinder segment of the body, which is capable of closing over them, so as to pre- serve them from being closed up by the fluid and putrid substances among which the larvse often live. The breathing apparatus of the aquatic larvae is often very singular, consisting of appendages of various OP INSECTS. 325 kinds attached to the tail. Those of the chamelion fly, the rat-tailed worm^ and many of the common, gnats, exhibit beautiful examples of ingenious natural mechanism. It is to the larvse of Diptera that we apply the common term maggots or maxvks ; some- times also they are termed grubs, but that appellation should be confined, for the sake of distinction, to the larvae of the Coleoptera. They are often very de- structive to corn and meadow grasses by eating the roots, and many of them, as is well known, rapidly consume animal substances, both in a dead and living state. The larvae of the flesh-flies, in particular, {Sarcophaga, and certain species of Mtisca,) infest living sheep, and frequently prove fatal to them. In the greater number of instances, the larva is changed into a pupa without shedding the skin ; the latter merely hardens, changes its form somewhat by contracting, and thus becomes a case for the en- closed insect. Sometimes, however, the skin is cast offj and even a kind of cocoon formed ; and the nymph occasionally retains the power of locomotion. This takes place only with such kinds as are aquatic. This order is a most extensive one, — indeed there is every reason to believe that it falls very little short of the Coleoptera in this respect, — and, if we re- gard the number of individuals belonging to many of the species, they will be found greatly to exceed all others. Clouds of musquitoes are common in Northern Lapland, and in other countries, so dense and extensive as to intercept the rays of the sun ; and, when we consider the small size of these insects. 326 SYSTEMATIC ARRANGEMENT it is obvious that the number necessary to do this must be astonishingly great. About 1700 have been named as belonging to this country ; and it is pro- bable that they will ultimately be found not to fall short of 2000. Allusion has been already made to the injuries they commit^ in the larva slate, both to our domestic animals and to agricultural produce; but the pur- poses to which they are subservient in the economy of nature, are highly important and beneficial. Many of the smaller birds, as well as some other of the higher animals, depend upon them almost exclusively for food, and they are the most efficient instruments employed by nature in removing both animal and vegetable substances when rendered offensive and unwholesome to other animals by decomposition. The most successful of the more recent investi- gators of this order are German and French Ento- mologists, particularly Meigen, Fallen, Wiedeman, Macquart, and Robineau Desvoidy. The following is Macquart's arrangement, slightly modified, for which we are indebted to Mr. Westwood's useful text-book : * Sbction I. (Ovipara or Larvipora ; Diptera, Leach.) — Head distinct from the thorax *, sucker enclosed in a labial canal ; claws of the tarsi simple, or with one tooth ; the transfor- mation to the pupa state not taking place within the body of the parent. Division I. (Nemocera.) — Antennse having six or more distinct joints ; palpi with 'four or five joints. * Page 420. OF INSECTS. 327 Fam. 1. (CuUcida.) — Sucker with six lancets. Fam. 2. {TipuUdce.) — Sucker with two lancets. Division II. (Brachocera.) — Antennae having three dis- tinct joints ; palpi with one or two joints. Subdivision I. {Hexachceta.) — Sucker with six lancets. Fam. Tabanidce. Subdivision II. {Tetrachceta.) — Sucker with four lancets. A. (Fam. CcenomyidcB^ Beridce, Stratiomi/da.) E. (Fam. Mydasidce^ AsilidcB, Hyhotidce, Empidce^ He- nopidcB, Nemestrinidce^ Bombyliidce, AntJiracidce. G. (Fam. TherevidcB^ Leptidce^ Dolichopidce, SyrphidcB. Subdivision III. [Dichceta.) — Sucker with two lancets, containing CEstrus^ Conops, Musca, ^c. <^c., with nume- rous divisions and subdivisions. Sectiov II. {Pupipara; Homaloptera, Leach.) — Head im- mersed in the front of the thorax ; sucker enclosed in two valves; claws with many teeth. The transformation to the pupa state undergone in the body of the parent fly. Fam. 1. (HippoboscidcB.) — Head frontal. Fam. 2. (Nycteribiidce.) — Head dorsal. Of the few examples, native and exotic, selected to illustrate the general appearance of the insects of this order, we shall first refer to CTENOPHORA PECTINICORNIS. Plate XXXIV. Fig. 1. Meigen^ Curtis. Tipula pectinicomis, Linn. Tip. nigro-crocea, De Geer. Tip. variegata, Fabr. Tip. splendor. Harris. In this genus the antennae are beautifully pectinated in the male, but simple in the female. It contains seven or eight British species, most of which are among the most ornamented of all the Tipulidae. The larvae appear to inhabit decayed trees. The species figured occurs not unfrequently in most parts 328 SYSTEMATIC ARRANGEMENT of the country. The upper parts of the head^ tho- rax, and abdomen are black, but the sides of a deep ochre or orange colour; wings smoke brown, the stigma dark ; legs ochreous, the tarsi dusky. TABANUS TROPICUS. Plate XXXIV. Fig. 2. Linn. Panzer, ^c. This exemplifies the well-known tribe of horse-flies, which are so troublesome in warm weather, by fix- ing on these animals, and sucking their blood. This species is not one of the most common, but it occurs now and then throughout the country. The anten- nse are ferruginous, dusky at the apex ; eyes green, with three transverse rays of purple ; thorax shining dark brown, with indistinct grey lines on the back ; abdomen black, the first four segments widely fulvous at the sides, and the segments margined with the same colour behind ; belly fulvous, dusky behind ; tibiae ferruginous, the anterior brown before the middle, the others generally somewhat dusky at the apex ; tarsi black. DIOPSIS ICHNEUMONEA. Plate XXXIV. Fig. 3. Donovan''s Indian Insects. This group presents the remarkable singularity of having the eyes placed on long footstalks, whence the species are sometimes called telescopic flies. The antennae are inserted on these lateral elonga- tions. The abdomen is narrowed at the base some- OF INSECTS. 329 thing like that of an ichneumon, and the thorax is armed with two spines. All of them are exotic, and hut a small number are known. The individual figured is from Bengal. It is of small size, not ex- ceeding four lines, (the figure being very much magnified,) the head, legs, and base of the abdomen yellow; the apex of the latter blue-black. The thorax is likewise of that colour, with a few white dots behind. The apex of the wing with a brownish black spot. ASILUS (BLEPHAROTES, West) ABDOMINALIS. Plate XXXV. Fig. 1. This represents a splendid insect belonging to the family Asilidae, but differing from all the species of that family in the broad flattened abdomen and in the structure of the intermediate tarsi. These pecu- liarities have led Mr. Westwood to propose a new subgeneric name for its reception. This insect is of an obscure brownish-black, with grey hairs; the nose is fringed with long fulvous hairs ; the basal segment of the abdomen is thickly clothed with grey hairs, the four following segments smooth, shining, and of a rich green colour, with the posterior margin whitish, the sides of these seg- ments are furnished with thick brushes of brown hair, those of the posterior segments being more mixed M'ith buff hairs; the terminal segment is corneous, and armed with two curved horny appen- dages; the legs are robust and black; the inter- mediate tibiae are short and clavate, with several 330 SYSTEMATIC ARRANGEMENT strong spines at the tip placed at right angles ; the hasal joint of the tarsi in these legs is singularly dilated at its internal base into a strong horny and toothed plate; the posterior tibiae are clothed with fulvous hairs ; the wings are pale bro^vn^ the basal lobe large and nearly black, the apical half of the "wing brown with the nerves margined, especially at the hinder margin of the wing, with whitish ; the third and fourth segments of the abdomen are fur- nished with a pair of tufts of black hairs; there is also a pair of more minute tufts on the fifth seg- ment ; halteres black. Inhabits New South Wales. In the collection of the Rev. F. W. Hope. " I have only seen," says Mr. Westwood, who furnished the drawing of this insect, '' males of this curious species. I possess another still larger species of Asilus from New Holland, agreeing with the preceding in the broad and flattened abdomen vdth lateral tufts, and which is evidently the Asilus Coriareus of Weidemann, (Auss. Zweifl. Ins. 2, p. 644,) although the description of that author being derived from a solitary and mutilated specimen is necessarily incomplete. Of this species I have only seen females ; and I have but little doubt that the insect here figured will ultimately prove to be the males of Weidemann's insect, notwithstanding the great diversity in their colours and general appear- ance. Both also agree in the peculiar direction of the subapical nerves of the wings." OP INSECTS. 331 ACANTHOMERA IMMANIS. Plate XXXV. Fig. 2. This represents one of the most gigantic Dipterous insects hitherto discovered, and which appears to be the Acanthomera Immanis of Weidemann, (Auss. Zweifl. Ins. 2. app. p. 623,) although the description of the author is very incomplete, the only specimen which he had seen being in a very mutilated state. The specimen here figured is nearly two inches long and three inches in the expanse of the whigs. It is a female, which sex differs from the males in the simple posterior femora, thus shewing the im- propriety of the generic name which is derived from the toothed posterior thighs of the males alone, (which only were known to Weidemann when he established the genus.) The minute silvery dots, arranged in curved series on the second, third, and fourth abdominal segments, are very peculiar. The specimen here figured is in the collection of the Entomological Club and was presented by G. S. Bowerbank, Esq. It is from Brazil. We have now completed our proposed review of all the orders of the Ptilota or winged insects. The three last orders indicated in the synoptical table, (page 200) include such genera as Pulex, Lepisma, Pediculus, Ricinus, and a few others of a similar nature, the general history of which forms a some- what distinct department of the subject, not of very general interest, and which it is no part of our plan to enter into at present. EDINBURGH : PRINTED BY T. CONSTABLE, PRINTER TO HER MAJESTY. EXTKKNAL AXATOiLY. n \Tr UIGE STIVE OR(i\Xs .V ClRCULATrNG^ X- RESPlKATdHT ORtVA^S. PLATE 4. NKRVOrS SYSTEM. CTene?ritu/e organs. 1. Ach eta. Jrachiioides. JO Wcsi^'o,dd^lt J, 9 ^,^^^^^. ^j^^ underside of the tJioraxojid ahdoiiit^n. oftheDonie^tic cri^Jcet. IBlntta^ii/ant^a 2.£hataTetn'eruma. 3.Ifrn^p(LV OceUariCL J/ \ Majitis Rehgios-a. JDeroplaJys distccata Thylliuni siccifolia 2 Acrul/i ver/ucjvora 3 Fte? ophi/lLcL ocdlfrttrc l.Locusta cnstaia. Z.Locusta fkj^/a t . 2 Folnieura ducalis LSaitrdU'raDispar' £>nlatoina nctilans SKjphi^^aster inranuUu,- PLATI ^- ■; ^ J«^' =^\ ., ?^"-^^ flf ^ t '^g^r ^^. I Mrtomu tj p nmh m'^ i t trbiu rlainhi'. j iin'^O'^ith Jmiunifilurru PLATE 2L y J. Cic€tda. plebeia. septendectm. PLATE 22. J^ I.Ful^ora laterriarui. ^ ^ ^ Castresii. FJ^XriB. 23. i^^ " l.Fulffora, candelaria $ 2. Tnaculata. PLATE 24-. ^ ^ LAphiina submaculo-ta. Q ?.Meinhracisfc^li