TEXAS AGRICULTURAL EXPERIMENT BULLETIN NO. 227 APRIL, I918 DIVISION OF ENTOMOLOGY STUDIES ON THE HARLEQUEIN BUG B. YOUNGBLOOD, DIRECTOR, COLLEGE STATION, BRAZOS COUNTY. TEXAS. AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS W. B. BizzELL, A. M., D. C. L., President TEXAS AGRICULTURAL EXPERIMENT STATION BOARD OF DIRECTORS ’ ' JonN I. GuioN, Ballinger, President ...................... .. L. J. HART, San Antonio, Vice-President... E. H. AsTiN, Bryan .................................................. .. J. R. KunENA, Fayettevill A. B. DAVIDSON, Cuero .... .. WiLL A. MiLLER, JR., Amarillo. JonN T. DICKSON, Paris . . H. A. BREinAN, Bartlett. F. M. LAW, Houston ................. ... . . . . . . . .. ............................. expires 1919 ....Term expires 1919 ....Term expires 1919 .. Term expires 1921 Term expires 1921 .Term expires 1921 .Term expires 1923 ...Term expires 1923 .............................................. Term expires 1923 MAIN STATION COMMITTEE L. J. HART, Chairman . WiLL A. MiLLER, JR. GOVERNING BOARD. STATE SUBSTATIONS P. L. DowNs, Tem le, President ............................ .. ustin, Vice-President .............. .. J. E. BOOG-SCOTI‘, Coleman .................................... .. W. A. JOHNSON, Memphis ...................................... .. CnARLEs ROGAN, .................................................... ..Term expires 1919 ..... ..Term expires 1923 ..... ..Term expires i923 Term expires 1918 ‘STATION STAFF ADMINISTRATION B. YOUNGBLOOD, M. S., Director A. B. CONNER, B. S., Vice Director CHAS. A. FELKER, Chief Clerk A. S. WARE, Secretary W. T. BRINK, B. S., Executive Assistant in Charge Library and Publication Enrrn PniLLiPs. B. S., Technical Assistant DIVISION OF VETERINARY SCIENCE “M. FRANcis, D. V. S., Veterinarian in Charge H. SCHMIDT, D. V. M., Veterinarian D. H. BENNETT, V. M. D., Assistant Veterinarian DIVISION OF CHEMISTRY _ G. . FRAPS, Ph. D., Chemist in Charge; State Chemist T. B. LEITH. B. A., Assistant Chemist ScoTT POWELL, B. S., Assistant Chemist SEICK, B. S., Assistant Chemist DIVISION OF HORTICULTURE _ H. NEss, M. S., Horticulturist in Charge W. S. HOTCHKISS, Horticulturist DIVISION OF ANIMAL HUSBANDRY J. C. BuRNs, B. S.,_Animal Husbandman, Feeding Investigations J. M JoNEs, A. M., Animal Husbandman. Breeding Investi ations P. V EwiNG, M. , Animal Husbandman in Charge Swine Investigations '*L. B. BURK, B Collaborating Animal Ilushanrlnzan. Sivine Investigations DIVISION OF ENTOMOLOGY F. . PAnoocR, l\l. S., Entomologist in Char e; State Entomologist H. J. %IE1NHARD, B. S., Assistant Entoé mologist E. JACKSON, M. S., Assistant Ento- mologist County Apiary Inspectors B. C. Abernathy, Ladonia; William Ateli- ley, Mathis; J. W. E. Basham. Barstow; T. W. Burleson, Waxahachie: \V. C. Col- iier, Goliad: E. W. Cothran, Boxton; G. F. Davidson, Pleasanton: John Donegan, Seguin; A. B. Graham Milan0;J. B. King, Batesville; N. G. Le ear, Waco; B. A. Little, Pearsall; S. H. Stephens, Uvalde; M. B. Tally, Victoria; R. E. Watson, Heidenlieimei"; F C. Belt. Ysleta; R. A. Nestor, Buffalo; J. E. Bush, San An- tonio; H. A. Jones, Oakdale; T. A. Bowdon, Palestine; E. B. Jones, Bee- ville DIVISION OF AGRONOMY A. B. CONNER, B. S., Agrpnomist in Charge A. H. LEinicH, B. S., Agronomist '**H. H. JOBsoN, B. S., Agronomist Louis WERMELsKiRcRr-N, B. S., Agronomist DIVISION OF PLANT PATHOLOGY AND PHYSIOLOGY I. J. TAUBENHAUS, Ph. D., Plant Patholo- gist and Physiologist in Charge DIVISION OF POULTRY HUSBANDRY R. N. HARvEY, B. S., Poultrgman in Charge DIVISION OF FORESTRY E. O. SIEKE, M. F., Forester in Charge, State Forester DIVISION OF PLANT BREEDING E. HuunERT, Ph. D., Plant Breeder in Charge DIVISION OF DAIRYING \V. A. DOUBT, Dairyman '"""SOIL SURVEY T. H. BENTON, Soil Surveyor J. F. STRoup, Soil Surveyor DIVISION OF FEED CONTROL SERVICE F. D. FULLER, M. S., Chief JAMES SuLLivAN, Executive Secretary J. H. ROcERs, Inspector W. H. Woon, Inspector S. D. PEARcE, Inspector W. M. WICKES, Inspecto: W F. CHRISTIAN, Inspector J W SNELL, Inspector J. J. KELLY, Inspector SUBSTATION NO. 1: Beeville, Bee County I. E. CowART, M. S., Superintendent SUBSTATION NO. 2: Troup, Smith (‘ounty W. S. IIOTCHKISS, Superintendent SUBSTATION NO. 3: Angleton, Brazoria County N. E. WiNTEns, B. S., Superintendent SUBSTATION NO. 4: Beaumont, Jefferson County H. II. LAunE, B. S., Superintendent G PuRvis. Scientific Assistant SUBSTATION NO. 5: Temple, Bell County D. T. KILLOUGH, B S., Superintendent SUBSTATION NO. 6' Denton, Denton County . H. MCDOWELL, B S., Superintendent SUBSTATION NO. 7: Spur, Dickens (‘ounty R. E. DICKSON, B. S., Superintendent SUBSTATION NO. 8: Lubbock, Lubbock ‘County R. E. KARrER, B. S., Superintendent DONALD JONES, Scientific Assistant SUBSTATION NO. 9: Pecos, Reeves County J W. JAcRsoN, B. S., Superintendent SUBSTATION NO. I0: (Feeding and Breeding Substation), College Station, ‘Brazos County E. B. SPENcE, B. S., Animat [Iushondman in Charge of Farm. G C. WARE. Scientific Assistant SUBSTATION NO. 11:- Nacogdoches, Naeog- doches Coun G. T. McNnss, Superintendent SUBSTATION NO. 12: Chiiiicolhe, Harde- man County . "“'**A. B. CRON, B. S., Superintendent V. E. HAFNER, B. S., Scientific Assistant SUBSTATION NO. 14, Sonora, Sutton County E. M. PETERs, B S., Acting Sitperintendent CLERICAL ASSISTANTS DAISY LEE, Registration Clerk C. L. DURsT, Mailing Clerk R. C. FRANKs, Stenographer W. L. HEARN, Stenographer MAE BELLE EvANs, Stenographer IRENE PEvERLEY. Copyist BUTn CAMPBELL, Steno rapher MARGARET SHELDON, BUTii LORD. Stenographer EMMA CAMPBELL, Stenographer H. L. FRAziER. Stenographer tenographer CONTENTS PAGE Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. '7 History . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . .v . . . . . . . . . . . . . . . . . . . . . '7 Distribution . . . . . . . . . . r-' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 Scientific name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1L1 Allied species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15 Common name . . . . . . . . . . . . . . . . . . . . . . ..; . . . . . . . . . . . . . . . . . . . .. 16 Economic importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Food plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ._. . . . . . . . . . .. 16 Methods of study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Life history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 Eggs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 Hatching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 Incubation period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20 Spring brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Summer brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 Fall brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25 Nymphs . . . . . . . . . . . . L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2'?’ Number of moults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- . . 2'7 Spring brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2'7 Summer brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . .. 28 Fall brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29 Duration of period of maturitty . . . . . . . . . . . . . . . . . . . . . .. 3O Spring brood . . . . . . . . . . . . . . . . . . ; . . . . . . . . . .2 . . . . . . 3O Summer brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3] Fall brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 Adults . . . . . . . . . . . . ..' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ... 33 Duration of life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34- “Proportion of sexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36 Duration of life cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37 Overivintering brood . . . . . . .' . . . . . . . . . . . . . . . . . . . . . . . . 37 ' Spring brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Summer brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3'?’ Number of generations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37 Feeding habits . . . . . . . . . .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Temperature influence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 _ - PAGE Location of food . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41 Adaptive capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 42 .Reproducfion . . . . . . . . . . . . . .i . . . . . . . . . . . . . . . . . . . . . . . . . . .. 42 Copulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 42 Period between maturity and copulation . . . . . . . . . . . . . . . . 42 Fertility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ._ . . . . . . . . . . 44 Oviposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 44 Age at beginning of ovip-osition . . . . . . . . . . . . . . . . . . . . . . . . 44 Period between copulation and oviposition . . . . . . . . . . . . . . . 46 Period of oviposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 46 Iiate of ovipositioni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. £48 lrotectiori . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51 Ilibernation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..' . . . . . . . . . . .. 52 Ehflrance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52 Stages entering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52 Congregafion beflnw lnbernafion . . . . . . . . . . . . . . . . . . . . . .. 53 Mortality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53 ]Durafion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Shelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Mortality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 55 Ehnergence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 55 Rehibernation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 56 First food . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 llatural control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 56 Climate . . . . . . . . . . . . . . . . . . . . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 I?arasites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 57 IEnennes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .;.... 57 Artificial control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,. . 57 1?all destruction, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 57 VVinter treatnient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58 Sfning treahnent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58 Cflean cufiure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58 Trap crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58 Iiennedial rneasures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Hand picking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59 Spraying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59 Sunnnary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 60 Idterature cfited . . . . . . . . . . . ., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 60 Bibhography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 61 1-," 4 . q ¢J‘**'“F'°?°‘-* ILLUSTRATIONS PLATES Opposite Page Types of life history rearing cages . . . . . . . . . . . . . . . . . . . . . . . .. 18 Cage shelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20 Large field cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 Cages used in hibernation studies . . . . . . . . . . . . . . . . . . . . . ‘. . . . . 24- (a) Plggs of harlequin bug; (b) young newly hatched; (c) color variation of broods.’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURES - Page Geographical distribution of the harlequin bug in North America 9 Distribution 0t the harlequin bug in Texas . . . . . . . . . . . . . . . . . . 11 Chronological distribution of the harlequin bug in the United States Generation series studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38 BULLETIN No. 227 ' ' APRIL, 1918 STUDIES ON THE HARLEQUIN BUG F. B. PADDOCK, M. S, ENTOMOLOGIST IN CHARGE; STATE ' ENTOMOLOGIST INTRODUCTION Almost every one in Texas who grows any garden is familiar with the insect known as the harlequin bug, often referred to as the fire bug, terrapin bug, and calico back. This insect seems to be present in almost every home garden and truck field in the State in which any cruciferous plants are- grown. And, when present, it is such a serious pest that it is dreaded by those who know it. The climatic condi- tions of the State are favorable for the develop-ment of this insect. The mild winters result in a low mortality of the hibernating bugs. Since this insect is practically free from the attacks of the predaceous enemies and parasites, the control of its depends entirely upon the grower’s effort. The studies here recorded on the harlequin bug were started in the spring of 1915 by the Writer. During the summer of 1916, cage notes were taken by O. K. Courtney, then Assistant Entomologist. Much credit ’ is due H. J .‘ Reinhard, Assistant Entomologist, for his painstaking work with the cage experiments while this project was in progress, and grate- ful acknowledment is hereby made. HISTORY This insect was first described by Hahn(1) in 1834 from material collected in Mexico, which material at that time was in his private col- lection in Germany. In spite of the fact that this species was first taken into Mexico, there seems to be some doubt that this country was the original home of this insect. In view of the fact that the remain- ing species of the genus are found in Central and South America and that later explorations show hisirionica to be well distributed in these countries, it is safe to conclude" that Central America. was the original home of the harlequin bug, Jlurgaintia histrionicai, Hahn. The next mention of this species was in 1851, when it was listed Dallas(2) in his “List of Hemiptera,” then found in the British Museum. He re- ported four specimens, three of which were from Mexico, and-the lo-' cality of the fourth was not given. A The occurrence of this insect in the .United States was mentioned for the first time by Benj. D. Walsh(3) in 1866 in an article in “The Practical Entomologist,” which incorporates the description of the in- 8 TEXAS AGRICULTURAL EXPERIMENT STATION. jury of the insect by Dr. Gideon Lincecum, of Washington county, Texas. This accurate early account is herewith produced: I “The year before last they got into my garden, and utterly de- stroyed 1ny cabbage, radishes, mustard, seed turnips, and every" other cruciform plant. Last year I did not set any of that order of plants in my garden. But the present year, thinking the bugs had probably left the premises, I planted my garden with radishes, mustard, and a variety of cabbages. By the first of April the mustard and radishes were large enough for use, and I discovered that the insects had commenced on them. I began p-icking them off by hand and. tramping them under foot. By that means I have preserved my 434 cabbages, but I have visited every one of them dailv now for four months. finding on them from thirtjv~five to sixty full grov/n insects every day, some coupled and some in the act of depositing their eggs. Although many have been hatched in the garden the ‘present season, I have suffered none to come to maturity; and the daily supplies of grown insects that I have been blessed with are immigrants from some other garden. “The perfect insect lives through the winter, and is ready to deposit its eggs as early as the 15th of March, or sooner, if it finds any cruciform plant large enough. They set‘ their eggs end to end in two rows. cemented together, mostly on the underside of the leaf and generally from eleven to twelve in number. In about six days in Ap-ril—four days in July—-there hatches out from these eggs a brood of larvae resembling the perfect insect, except in hay-- ing no wings. This brood immediately begins the work of de- struction‘ by piercing and sucking the life-sap from the leaves; and in twelve days they have matured. They are timid, and will run off and hide behind the first leaf stem, or any part of the plant that will answer the purpose. The leaf that they puncture imme- diately Wilts, like the effects of poison and soon withers. Half a dozen grown insects will kill a cabbage in a. day. They continue through the summer, and sufficient perfectinserts survive the win- ter to insure a full crop of them for the coming season. “This tribe of insects do not seem liable to the attacks of any of the cannibal races, either in the egg state or at any other stage. Our birds pay no attention to them, neither will the domestic fowls touch them. I have as yret found no way to get clear of them, but to pick them off by hand.” ' In his article, Walsh speaks of this insect as occurring in Texas and Louisiana. , The year 1864- is assumed as the date of the introduction of this species into the United States. This date, however, is the first. record of the insect as a. pest, at a point some distance from the Mexican border. The Mexican cotton boll weevil, even with its rapid spread was six years in getting as far from the Mexican border as the first locality given for the harlequin bug. Furthermore, the records made in 1864 in Washington county indicate that the pest had been present in that locality in vast numbers for some time. lt was sixyea-rs later STUDIES ON THE HARLEQUIN BUG. 9 t‘ before mention was made of’ this insect at Austin, in Travis county, i eighty-five miles West of the first reported locality and no farther from I the Mexican border. From this, it would seem that this pest crossed the border several years previous to 1864;. In January, 1870, (l. V. Riley in “The American Entomologistw/L) recorded the presence of this insect from Salisbury, North Carolina, M U’ ‘ .3 . L-J . Fig. L-Geographical distribution of the harlequin bug in North America. (Original) and said: “It seems to be as great a pest in the gardens of that state . as Dr. Lincecum describes is to be in 'l‘exas.” In March of the same year, J. S. Stelle(5), of Tennessee, in the same publication recorded the date of occurrence of this insect in Georgia, Alabama and Missis- v sippi, and gave a vivid account of the progress of the pest northward . through these states into Tennessee. 1O TEXAS AGRICULTURAL EXPERIMENT STATION. In the following year Stal(7) listed this species in the present genus in his “Enunieratio Hemipterorum.” The specimens were present in the museum at Stockholm, and the distribution was given as “Mexico, Texas and Louisiana.” Riley(8) again wrote on this insect in 1872 in his “Fourth Report.” He said that prior to 1870 this species was not present in Missouri, but in the two years previous to his Writing the harlequin bug had been found in some of the southern counties of that state, and in Kansas it had been found as far north as the latitude of St. Louis. He said that “this species now extends as far south as Guatemala.” In 1880, Godman and Salvin(10) discussed this species, carefully, giving synonyms, bibliography, distribution to date and, briefly, the main points of life history. The distribution included Arizona, Cali- fornia, Colorado,'Delaware, Florida, Indian Territory, Louisiana and Texas; Oaxaca, Mexico; Capetillo, Duenas, Purula, San Geronimo, Guatemala; and Costa Rica. In the same year Lintner(11) told of the presence of this insect in Virginia. In his paper he warned the vege- table growers of New York to acquaint themselves of the appearance of this insect, so that they would be able to combat the pest when it ar- rived in that State. He expressed confidence that the pest would eventually reach New York, and finally spread over the entire state. DISTRIBUTION The year following the first report of this insect in Texas, it was reported from Louisiana by W alsh( 3), although no localities were given by him. In the fall of 1867. Rileyfll) reported the presence of this insect in Salisbury, N. C. Stelle(5) says that in 1867 this insect was found in the Carolinas near the Coast; at Macon, Georgia; Tusca- loosa, Alabama, and Columbus, Mississippi. In the fall of the follow- ing year he says that the fall brood appeared along the northern boun- dary line of Mississipp-i and Alabama. In 1869, Stelle recorded the occurrence of the harlequin bug at Humboldt and Nashville, Tennessee. .Riley(8) tells of the presence of this insect in 1870 in the southern counties of Missouri and in Kansas as far north as the latitude of St. Louis. Uhler(9) in his exploration trips through the western territories found this insect in the Indian Territory, Arizona, California, Nevada, and Colorado. In another paper Uhler said: “Its introduction has been etfected since the late war (Civil War) and now (1.875) it is known as far north as the vicinity of Pennsydvania. boundary line in Delaware.” By 1876 this insect was quite common in the Ohio counties adjoining the river. Specimens were sent to Lintner from Ivy Depot, Virginia, o-n September 24, 1880, but did not become abundant enough to cause extensive destruction of crop-s until 1894. In 1889 this species was recorded at Las Vegas, N. M., where it was said to have existed “from the time irnmemorial.” The first record of this insect in Indiana. came in 1890. In New York it was not until 1894 that this insect attracted, attention of the growers in the southern part of the state, but it was not until 1910 that isolated specimens were found as far north as Oswego, on Lake Erie. According to Webster STUDIES ON THE HARLEQUIN BUG. 11 this insect at one time reached as far north as Chicago, Ill., and almost to the shore of Lake Erie in Ohio. "In 1910 specimens were also taken at Meridian, Conn., and in 1912 isolated specimens were again taken close to the shore of Lake Erie, after an absence in this locality of many years. It is to be regretted that all of these early dates given do not repre- sent the first appearance of the insect in the state. In fact, most of the early references are to the insect as a serious pest doing great dam- age. Every effort has been made to secure the exact _date of the first appearance of this species in a state. Fig. 2——Distributi0n of the harlequin bug in Texas. (Original) An idea of the distribution of the hairlequin bug can be had by ref- erence to figure 1. In this no attempt has. been made to show every locality in the United States Where it is to be found at present. It will be observed that this species has been found over a range of from 10° to 43° 38’ N. latitude. The most southern locality was recorded in 1880, at which time the most northern place attained was 38° N. latitude. The harlequin bug is now reported from the following states: Ala- bama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Georgia, Florida, Indiana, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Missouri, Nevada, Neur Jersey, New York, New Mexico. _ 12 TEXAS AGRICULTURAL EXPERIMENT STATION. North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Ten- nessee, Virginia, and Texas. _ Figure 2 gives the distribution of the insect in Texas as indicated by reports of injury that have come to ha.nd. While the reports are most numerous from the eastern or humid section, it is evident that in this state the distribution of the pest is governed only by the distribu- tion of its food plants. DTSPERSION From the rather incomplete records available it is possible to trace the general spread of this insect over the United States. Reference to figure 3, a map of the chronological distribution, will show how diffi- cult it is to‘ attempt to determine the exact lines of travel. The fact of incomplete early records will account for the apparent rapid spread in those times. During the more recent years the spread northward has been steady and quite consistent. It is hard to explain the spread I 18700 ay~“~+»l Fig. 3.~—Chron0logical distribution of the harlequin bug in United States. (Original) satisfactorily by what some Writers term “commercial jumps.” Such a spread is not wholly borne out by the facts of the life history, even though it might be accomplished. Stelle(4-) as early as 1870 gave a very good account of the gradual northward spread of this insect. He. said in 1867 it was present as far north as Tuscaloosa, Alabama, and Columbus, lVIississippi. The fall brood‘ of. 1868 appeared along the Tennessee line. The next year both broods Were abundant at this latitude and in the following year appeared as far north as Humboldt and Nash- ville, Tennessee. Between 1868 and 1869 the species spread northward for 50 miles. The harlequin bug originated in the tropical life zone and no doubt came into the United States through that zone, which extends into ’l‘exas for a very short distance. Its early appearance in California Srunrns on THE HARLEQUIN BUG. 13 and Arizona can be explained from the projection between these states for a very short distance of this zone from Lower California and Mexico. The spread in California Was very slow, however, for as late as 1889 it wa.s reported from only three counties. It ‘has been supposed that this insect spread first over the lower austral zone. We find, however, early mention (1870) of its presence in Kansas in the upper austral zone, and as early as 1875 it was reported from Denver, Colorado, in the transition zone. The first reports from Mississippi, Alabama, and "South Carolina in 1867 were from the lower austral zone. The report of the same year from Georgia came from the upper austral zone, and the locality in North Carolina-for the same year was in the upper austral zone at the edge of the transition zone. The spread northward in Mississippi was through the lower austral zone, and in 1869 speci- mens were taken from Louisville, Kentucky, in the upper. austral zone. From that time, the spread was rapid along the Atlantic seaboard, following the line of the upper austral zone. This spread was sepa- rated from a much slower spread in the Ohio valley region by a pro- jection southward by the transition and boreal zones. This insect ap- peared early in the Ohio counties bordering on the river, but the sp-read northward was very slow. For a time it appeared as though the insect had stopped along the line of division between the glaciated and un- glaciated sections of the country. It was fourteen years later before a single specimen was found in the glaciated area, this being in Indiana. This insect was found in the three northernmost localities in 1910. In Connecticut the locality was in the transition zone; in New York, in the transition zone, at the very edge of the boreal zone; in Ohio, in the transition zone. This insect has not become permanently established as far north in New York as isolated collections would indicate. It is, however, gradually working northward, overcoming the climatic limi~ tations. The effect of temperature upon the spread of an insect of tropical origin has always been an interesting subject. Today we are some- what inclined to disregard this problem, but a study of this insect shows that climate has been a very important factor in its spread. The early writers gave considerable study to the effects of climate upon a probable spread of this insect: - Stelle(5) said in 1870: “So far, the change of climate docs not seem to have affected this insect in the least,—it was as destructive and numerous along the southern line of Tennessee last summer as it had been previ- ously at any point further south. A careful study of its charac- ter has uiarranted me in predicting that it will scarcely stop short» of the Great Lakes.” In 1882 Lintner( 10) said that since the species is aipest at Denver, Colorado, it “is capable of sustaining itself even north of the isothermal line of 40° Fahr. Allowing it this range will ad- mit of its future extension into the western states, at least over the southern portion of Minnesota and Wisconsin, and eastward, 14 TEXAS AGRICULTURAL EXPERIMENT STATION. entirely over the states of New York and Vermont, the southern portions of New Hampshire and Maine, a large portion of the province of" Quebec. This extension, We believe, will be only a question of time, for its progressive march seems to be steady.” Contrary to these early predictions of the northward travel of this insect, since 18801 thespread has been very slow, and extremely cold winte-rs have had a decided effect in preventing its spread. In December, 1899, Wel>ster(12) said: “The harlequin cabbage bug, Zllurgantia hvistrionica, has certainly sustained a severe repulse by the low temperature of last winter. While the insect was observed in southern Ohio last May, its al- most entire absence has been reported in localities where last year it was disastrouslv abundant. From this it would appear that only the most hardy or best protected individuals have survived in Ohio, and We may now look for it to attemp-t again to push its vray northward until it is once more driven back by adverse meteorolog- ical conditions.” Again in 1901(13) he said: “The ‘harlequin cabbage bug, which was Qxterminated by the severe winter a few years ago, has begun its northward spread again, and has been reported as destructive at points along the Ohio river.” The insect was exterrninated the same ‘year in Maryland and Delaware and was not found in that territory again, even in the isolated colonies, until 1908. At this latitude the insect is a pest of cultivated crops only after a very mild winter. Even now it may be found late in the fall on some wild food plants. Sanderson(14) considers the harlequin bug as one ‘of the insects whose distribution is considered as more or less controlled by minimum temperature. He says: “The northern limit of this species follows the average annual-minimum isotherm of 0° G. much more closely than the upper austral zone. It- may yiet migrate to northern Ohio and On- tario, but further progress seems doubtful.” SOIENCFIFIC NAME Hahn(1) in 1834- described the harlequin bug as Strachia histrionica, a genus which has been established for several years. In 1851 Dallas (2) listed. this species without any change, although he did revise and establish synonyms for other species. The first reference to this species in American literature was by Walsl1(3), when he placed the insect in the family Scutelleridrze of the order H cterogaterra. Following in 1870, Rileyfl) called the harlequin loug bltrnclz/ia histrion/ica, as did Stelle in another reference to the species in the same year. ‘ In 1867 Stal erected the genus ilhufiqantia and in his work (7) in 1871 he placed this genus in the sub-family Pentatomina, also erected by him, and in the family Cimicina erected by him, in a section called “Enumeratoio Cimicinorum Americae.” He placed ltistrionioa_. Hahn, as the only example of a division of the genus, “aai. Antennis brevibus; STUDIES ON THE HARLEqUlN BUG. 15 Thoracc margineum auticum pluvnctis absileiis seriopositis instructo- margine i080 calloso, elevate; corpora sizbtus nigro, maculis alhidis et crocetls in series disposvit/io omata.” Evidently the work of Stal was received promptly in the United States, for Biley(8) in 1872 gave the scientific name as- Strachia (Murgantia) ltistrioni-ca, Hahn. The na.me, M. histrionicai, Hahn, has been accepted by all writers since that time. Lintnnr(11) in 1882 placed this insect in the family Cyanidae of the sub-order H eteraptera. Later it was placed in the family Pentatomi/Zae, where it now stands. ALLIED SPECIES Stal in his work in 1867 listed a species. M. munda DaIlas, which was named by Dallas in his work in 1851. Stal places munda in another division of the genus illurganzt-ia, characterized in distinctions as fol- lows: “a, Antennis Zongis; thorace pwpemrargineunt anticumr punc- tato, hoe ‘margine land rel cit eleoaio; corpora surbtus flfizrvescute, maculis Zateralibus caerleis we! cisllaceis.” This species is listed from Mexico and Columbia. i Riley(8) in 18m Said! “It (the harlequin bug) varies very much, as most species are found to do when their geographical distribution is studied. As it extends southward we find the dark colors predominating and becoming more intensified and lurilliant, and described a. species (Murgant/ia. mun/lat) from Mexico, which is doubtless but a geo- graphical race, since all the intermediate grades occur between it and the more northern form of hisirionaica. My friend, P. R. Uhler, has made some interesting experiments. on the species, which have clearly proven that when reared in the dark the pale red plarts predominate; while if reared in ‘the bright daylight, the dark blue colors predominate.” On this same matter Distant(10) in 1880 quoted further from Uhler as follows: “Several of the links in the chain of varieties between this species histrionica and M. mlunda have already been found, and we may expect hereafter to see the two species united as mere forms of one.” Speaking further, Distant said: “lVc ourselves, however, have seen nothing as yet to warrant such a probability. The specimen figure is from Guatemala, and, excepting slight variations, is the dominate form in Central America. Hahn’s ‘figure would seem to represent a melanic and (judging from my own experience) scarce form of this species.” Notwithstanding these opinions, we find that in 1891, in “Insect Life,” we have received specimens fromlCalifornia, which are probably Zllurganfzia. murnda. Since the time of Uhler’s quotation there has been no reference to mruwda and it is quite possible that later studies have f convinced entomologists that there was insufiicient reason for maintain- ing two species, regardless of the fact that Stal considered them ana- l tomically separated. Any extended study of this species will reveal that m, 16 TEXAS AGRICULTURAL EXPERIMENT STATION. the color variation is very considerable and is not constant. In addi- tion, there is a seasonal variation; the fall brood is much darker than the spring and summer broods. Riley(8) mentions the presence i.n Europe of Zllurgantia (Strachia) omatai Linn, a species “xvhich bears a striking resemblance to our in- sect in color and ornamentation, and which, as I was assured by M. E. Mulsant, of Lyons, France, has the light parts red in spring and yellow in autumn.” This insect is a serious pest of cabbage. COMMON NAME In 1866 Walsh(3) wrote of the insect as the Texas cabbage bug. In 1870 Riley(4) said: “Hitherto it had been generally supposed by en- tomologists that the harlequin cabbage bug was confined to the most southerly of the southern states, such as Texas and Louisiana, and it has been called by some ‘The Texas cabbage bug,’ ” instead of translat- ing the scientific name and calling it as we have done, the “harlequin cabbage bug.” This so-called translation seems a little arbitrary, al- though the word harlequin (gay colored) describes the insect very well. Ifistrionica is undoubtedly derived from histrio, meaning actor. Of late years there has been a tendency t0 say merely harlequin bug, as the insect attacks a wide variety of plants and its chief injury is not always to cabbage. ‘ Especially is this true in Texas where winter crops of collards, mustard, a11d turnips are often destroyed bythis insect. It is known locally as the collard bug, terrapin bug, calico bug and fire bug. ECONOMIC IMPORTANCE Most of the early writers did not fail to impress on their readers the great destruction accomplished by this insect. The original discussion by Dr. Lincecum mentions the “utter destruction of cabbage, radish, mustard and turnip,—finding from 35 to 60 full grown insects on every, plant.” Riley in 1870 said that in North Carolina it seemed to be "as great a pest as in Texas. And he quoted from B. B. Town- send, Austin, Texas, “Within a few days he had gathered, by hand, 47,000 bugs.” Stelle in 1870 said: “Last year it worked wholesale destruction.” Lintner said in 188]: “This insect entirely destroy*c<:l the cabbage cro-p in a section in ‘Virginia. Its distribution over the northern portion of the United States cannot but operate as a serious check upon the culture of cabbage.” Between 1892 and 1893 this in- sect was a. very destructive one in cabbage fields in Delaware. In Texas where the mild winters do not serve as a substantial check, this pest causes much damage every year to all of its cultivated host plants. In most sections the home gardens suffer severely from the attacks of the insect, and in truck regions unlimited damage is done. FOOD PLANTS From the name commonly applied to this insect it might be inferred that cabbage was a primary food plant. The harlequin bug, however, STUDIES ON THE TTARLEQUIN Bus. 1'7 feeds upon many members of the Cirucifera-e family’, not only the culti- vated but some of the wild species. As the insect advanced northward, i it was always feared as a cabbage pest, for in new territory its work seemed to have been most. apparent on this host. Even now in the northern section of its range, this insect docs most damage to cabbage. Throughout the South it is very destructive to winter truck cro-ps of turnips, mustard, and collards. The feeding of the harlequin bug is not confined to the Uruciytcraé but it has a wide range of host plants. The following plants have been observed to serve as food plants for the harlequin bug in 'l‘exas: Amaranfihrus spinosvis, cabbage, cauliflower, citrus (orange, grape fruit and loquet), collards, corn, cotton, egg plant, grapes (cultivated), kale, kohlrabi, lettuce (cultivated), mustard, nas- turtiums, okra, cowpeas, pepper grass (Lepedim), rag weed (Ambrosia- sp.), rape, rock cress (Arabia Zudaciciaata Hork), rutabaga, and squash. Amar-anihus spines/is serves as a. host of this insect in July at a time when there are almost no succulent plants in this vicinity. Cabbage is attacked at any time that it is available in the fields, which is also true 0f cauliflower. The feeding on citrus is largely confined to the fall; the very ripe fruits are attacked, especially if the skin is broken. Collards are subject to attack during the fall, winter and early spring; this plant often serves as a winter host of the insect. In July the in- sects were very numerous on corn, all stages and eggs being observed on this plant. Cotton is attacked during August and September at a time when few vegetables are succulent. The bugs pierce the medium-sized ‘bolls, which does not seem to prevent the latter from opening. Egg plant is seldom attacked, but all stages of the insect have been taken upon this plant. Grapes seem to be attacked only after the favorite ‘food plants have been destroyed in June. Kale is not preferred and is attacked in the late spring only after mustard and collards are no longer available. Kohlrabi is not readily attacked and for that reason the plants are seldom entirely destroyed. Lettuce is attacked in the spring only after the "favorite food plants have been destroyed. Mustard is readily attacked, especially in the spring. Only one instance is recorded of the cabbage bug feeding on nasturtiums and this was after turnips in an adjoining patch had been destroyed. Okra serves for feed -0nly at times ‘during the summer; eggs have not been found on this host. Throughout the month of July the harlequin bug feeds on cow- ‘peas. Eggs are also deposited on this host. Pepper grass was observed to serve as a. host in March, at which time cabbage was also available "in the same garden. The insects seemed to prefer this host to all others at that time. Radishes are attacked any time they are available and the crop is readily destroyed. Rape serves as a food plant only after "the favorite food p-lants are destroyed. ln the early spring the cabbage bug is observed feeding on the rock cress, although‘ only for a limited period, and no eggs were found on this host. Rutabaga turnips are not readily attacked, except in the absence of i »a favorite host. In the early fall the bugs have been found feeding on t squash butlno eggs have been found deposited on this plant. Turnips :are readily attacked at any time. r 18 TEXAS AGRICULTURAL EXPERIMENT STATION. In addition to the host plants listed above for Texas, Garman says wild mustard serves as a. host in the early spring. Webster reports the cabbage bug feeding on horse radish. Ohittenden records asparagus, potatoes, tomatoes, beans and beets as plants that may be attacked. Damage may also be done to roses, sunflowers and Chrysanthemums Cherry and plum have served as food for the bugs. Pig weed (Ama- ralnthus sp.), wild lettuce (Lactuca canadensis), and lamb’s quarter (Chenopodizem sp.) serve as food plants for the harlequin bug. It is also possible for this insect to breed on any of these weeds. METHODS OF STUDY For the purpose of observing the details of the life history of the harlequin bug, specimens were isolated in cages. The type of cage first used in this work is shown in plate 1, (a) a lantern globe with a cover of cheese cloth. In this cage, fresh food was placed daily, which usually consisted of collard leaves or cabbage leaves, taken from the growing plants in the field when possible. This method of supplying fresh food to the bugs required the transferal of them each day on to the fresh food. During the summer season, the food would not remain in good condition as long as twenty-four hours, For this reason, the use of this type of cage was not wholly satisfactory. Later, a new type of cage. plate 1 (b),f»vas adopted for the life history studies. This cage con- sisted of a large street lamp globe No. 3. On the bottom of this is a tight collar made of a. two-inch strip of brass screening; the top is made of similar material. This cage allows a free circulation of air over the food "material, which keeps it in good condition for a consider- able period of time. To avoid the transferal of the bugs each day, grow- ing plants in eight-inch pots were used. These plants were usually collard, although some cabbage plants were used. The larger leaves were trimmed off so that the plant would fit well into the cage. The plants were kept in excellent condition and usually a single plant served to mature a generation of bugs. The hatching egg masses were placed on these plants and the bugs were observed throughout the duration of their lives. By daily observations it was very easy to determine the moults of the immature bugs and the daily egg deposition of the mature bugs. All of the cages were kept in the shelte” shown in plate 2. For seasonal history observations two types 0L cages were used. The large cage shown in plate 3 is 4 feet by 6 feet by 6 feet, covered with wire screening, and built so as to be taken apart in sections. The eage- was placed over several kinds of plants to determine the preference, if‘ any, of the hosts during the YQHY.‘ Another cage of the same type was used for general hibernation studies. The cages shown in plate 4 were used for special field observations of the life history, particularly hiber- nation studies. The xvoods shown in the distance served as natural‘ hiberating quarters for the harlequin. bug. This allowed extensive notes to be made under actual field, conditions to serve as a check on the- cage notes. l - (a) (b) Plate 1.——(a) Type of rearing cage first used; (bgotype 01f cage adopted for all life history experiments. rigina ) wrwmwp- “vwfifl-qvl- . . . STUDIES 0N THE HARLEQUIN BUG. 19 TJIFE HISTORY The life history of the harlequin bug has been mentioned by a. num- ber of the early xvriters in a more or less indefinite way. Dr. Lincecum in his early account of this insect gives several very interesting obser- vations,-such as the number of broods, the hibernation, and the length of the egg stage. Most writers have quoted these observations and added a few local notes, in an effort to outline the details of the life history. Among the more recent publications are the papers by Smith that give the results of his experiments, which consist of the detailed observa- tions of the life history of the insect. In our work we have arbitrarily set- dates which have assumed the natural divisions of the broods during the year. There is, of course, a very considerable overlapping of the broods during the year, but de- tailed cage studies have enabled us to arrive at the actual number of broods during the year. We designate the Spring brood as those in- sects that develop from eggs hatched before June 1; the Summer brood, those insects which. develop from eggs hatched from June 1 to August 15; the Fall and over-wintering brood, those insects hatching from eggs deposited from _August 15 to October 15. Most observations have shown that eggs deposited after September 15 will not always develop into mature bugs, which are the only ones that can successfully pass the winter. EGGS The egg is cylindrical and rounded on both ends. When first de- posited, the eggs are a light green in color but soon become white with black markings. Running around the egg are two black bands, the one near the top being about twice as wide as the one near the bottom. Just above the lower band is one black spot. On the top end of the egg is a black crescent which borders a slightly depressed lid. This crescent extends half around the lid, being always on the outer side of the egg mass. There are no markings on the lower end of the egg which is much rounded, Whereas the top is much flattened. When first deposited the eggs are covered with a glue which fastens the egg to the leaf and to the adjoining eggs. After drying the eggs are very hard and the dry mass can be loosened from the leaf, but it is very difficult ‘to separate the individual eggs. The average size of the eggs is '75 _mm. long and 1.25 mm. wide. Plate 5, (a) shows an egg mass of the v harlequin bug. HATCHING The process of hatching attracted attention of the investigators as - early ds 1872. Previous to hatching, the egg loses the pearly white _ color and appears yellow to orange from the developing bug. The young ~ insect cuts the shell in the upper end of the egg at the outer edge of ‘the black crescent. This cut is verv smooth and accurate and extends only slightly beyond the lengfth of the crescent. Thus a lid to the egg is formed by the portion remaining uncut. The young insect emerges _ from the egg dorsal side outward. l There seems to be much resistance l‘ in that portion of the shell which is uncut and the insect apparently t "20 l TEXAS AGRICULTURAL EXPERIMENT STATION. has to “squeeze” out of the opening with much effort. Emergence is accomplished, with the exception of the tip of the abdomen, which is held firmly by the shell, thus holding the insect in an erect position. It remains in this position for some time while the parts harden, which ‘enable it to move ofl’. The batch. of eggs hatches irregularly, which allows freedom to the _voung bugs in (luring. One bug is drving and moving off before the adjoining egg hatches. From the timepthe shell is cut until the young bug is dry, all the time of hatching, is about ‘forty minutes. After hatching, the young remain clinging to the sides of the egg shells, as shown in plate 5 (b), for about thirty-six hours before moving off onto the plant forfeeding. INCUBATION PERIOD. The period of incubation varies greatly with the brood and seasons in proportion to the fluctuations in temperature. The effect of humid- ity upon the incubation period has not been determined but as it is recorded, it is given in the tables. The recent papers on the effect of the humidity on insect metabolism seem to indicate that this factor can be disregarded in insect studies. The low temperature at which the vitality of the eggs is destroyed has not been determined. In the following tables the maximum is the highest single tempera- ture during the period; the minimum is the lowest single temperature ‘during the period. The mean given in the tables is the average of the mean daily tem- perature of. the days in the period. The determination of the length of the period has been made by placing the freshly laid eggs with a. piece of leaf on which they were deposited in a small lantern globe cage. - The cages were kept under natural conditions which were recorded by ' "the hydro-thermograph. ' Spring Brood Table 1.——Duration of egg stage, brood, 1915. _ Temperature. Humidity. Laid. Hatched. Days. Max. Min. Mean. Max. Min. Mean. 1915 1915 Mar. 12 April 9 . . . . . . .. 28 87 34 54 7 100 26 7O 5 15 1O . . . . . . .. 26 87 34 56 6 100 26 73 4 17 12 . . . . . . .. 26 87 34 58 4 100 26 73 9 16 . . . . . . .. 17 87 34 62 3 100 26 69 4 April 5 16 . . . . . . .. 11 85 55 - 7O 3 100 30 72 2 17 . . . . . . .. 10 85 55 71 2 100 30 71 4 8 19 . . . . . . .. 11 85 54 70 7 100 30 7O 8 11 21 . . . . . . .. 10 85 54 70 7 100 30 73 2 12 22 . . . . . . .. 1O 85 54 7O 6 100 30 74 1 19 29 . . . . . . .. 10 83 57 7O 9 100 63 89 7 20 30 . . . . . . .. 1O 86 57 71 8 100 63 90 2 21 May 1 . . . . . . .. 1O 86 61 71 9 100 63 89 2 22 2 . . . . . . .. 10 86 61 71 9 100 64 90 1 26 3 . . . . . . .. 7 86 66 74 9 100 6-4 89 2 27 6 . . . . . . .. 9 86 61 72 6 100 64 86 1 29 8 . . . . . . .. 9 86 60 72 1 100 64 86 3 May 4 23 . . . . . . .. 19 92 53 75 100 33 75 2 The longest period of this brood in 1915 was 28 days with a mean ~daily temperature of 57° 1T; the shortest period for this brood was 7 days with a mean temperature of 74.9° F.; the average period ofthis brood was 13.7 days with a mean daily temperature of 68.6° F. 15$ Mwlflmmm mWQZmw 953m 25 S? 532% ovmnzmwmosm $68 Emma. AOlmwbmc STUDIES ON THE HARLEQUIN BUG. - 2]. Table 2._—Duration of egg stage, brood——l916. _ Temperature. Humidity. Lald. Hatched. Days. a NIax. Min. Mean. Max. Min. Mean. 1916 1916 Feb. 2 Feb. 26 . . . . . . . . 24 89 25 55.9 100 22 67.5 28 Mar. 6 . . . . . . . . 7 89 37 59.7 100 26 53.8 28 14 . . . . . . .. 14 89 37 63.3 1OO 12 63 Mar. 1 1O . . . . . . . . 9 89 37 55.9 100 12 63.5 6 14 . . . . . . .. 8 89 54 71.1 99 12 63.5 9 2O . . . . . . .. 11 89 44 65.7 98 22 59.2 14 2 . . . . . . .. 9 94. 44 68.4 98 22 61.2 23 Aprll 4 . . . . . . . . 12 89 41 68.3 100 17 63.5 25 Mar 3O . . . . . . .. 5 89 41 65.2 1OO 18 59.1 25 30 . . . . . . .. 5 89 41 65.2 1OO 18 59.1 27 Apr1l12 . . . . . . .. 16 89 31 63.5 9 18 66.7 _ 7 12 . . . . . . .. 16 89 31 63.5 99 18 66.7 Apfll 5 18 . . . . . . . . 13 89 31 65.6 1OO 22 70.3 18 . . . . . . .. 12 89 31 65.7 1OO 22 79.9 11 20 . . . . . . .. 9 9O 31 1.6 100 30 69.7 14 23 . . . . . . . . 9 9O 50 62.8 100 19 66.6 15 23 . . . . . . .. 8 90 50 72.8 100 19 66.3 18 25 . . . . . . .. 7 9O 5O 72.8 98 19 62.7 23 May 4 . . . . . . . . 11 91 47 68.2 99 22 71 May 1 9 . . . . . . . . 8 90 53 70.1 99 30 74 3 9 . . . . . . . . 6 9O 53 70. 6 97 30 70.7. 8 13 . . . . . . . . 5 94 69 80.3 98 35 66.1 10 17 . . . . . . . . 7 94 59 81 97 3O 66.8 13 20 . . . . . . .. 7 92 56 74.8 100 31 68.8 14 22 . . . . . . .. 8 92 56 73.8 100 3O 71 .8 24 29 . . . . . . . . 5 92 68 80.8 98 42 74.9 31 June 5 . . . . . . .. 5 98 46 72.1 98 39 68.8 The longest period of this brood in 1916 was 24 days, with a mean temperature of 58.9” F. _; the shortest was 5 days, xivith a mean temper- ature of 727° F. The average period of this brood was 9 days, with a mean temperature of 689° F. Table 3.——Duration of egg stage, brood—-1917. _ Temperature. Humidity. Lald. Hatched. Days. _ Max. Min. Mean. Max. Mm. Mean. 1917 1917 " J Mar 1O Mar 23 . . . . . . .. 13 99 49 71 98 17 65 4 25 . . . . . . .. 12 99 49 71 4 96 17 61 2 17 29 . . . . . . .. 12 98 49 71 8 95 12 55 4 17 31 . . . . . . .. 14 99 49 72 5 95 12 53 3 18 29 . . . . . . .. 11 99 49 72 9 95 12 55 3 22 29 . . . . . . .. 99 5O 76 4 95 12 53 3 23 Aprrl 1 . . . . . . . . 9 99 5O 73 8 95 12 54 25 . . . . . . .. 11 99 42 73 5 96 12 54 4 25 6 . . . . . . .. 12 99 42 71 9 96 12 54 4 25 7 . . . . . . .. 13 99 42 7O 5 96 12 53 9 27 . . . . . . .. 5 99 50 76 5 94 16 51 4 29 1O . . . . . . . . 12 99 41 58 96 18 57 9 29 11 . . . . . . .. 13 99 41 66 4 96 18 59 5 3O 14 . . . . . . .. 15 99 41 6a 8 97 18 59 7 April 1 15 . . . . . . .. 14 84 41 62 7 97 18 59 5 2 15 . . . . . . .. 15 78 41 61 5 97 18 59 1 3 18 . . . . . . . . 15 82 41 63 97 18 65 O 5 19 . . . . . . .. 14 82 41 64 2 97 18 62 6 6 19 . . . . . . .. 13 82 41 64 8 97 18 62 5 1O 22 . . . . . . . . 12 82 47 68 97 29 67 4 11 21 . . . . . . .. 1O 82 49 69 1 97 3O 68 6 14 25 . . . . . . .. 11 84 49 69 9 95 2O 65 4 15 24 . . . . . . .. 9 84 49 7O 7 95 2O 66 1 15 25 . . . . . . .. 1O 84 49 7O 8 95 2O 65 1 17 26 . . . . . . .. 9 84 56 72 3 95 2O 65 5 17 27 . . . . . . .. 1O 87 56 72 4 95 2O 65 8 19 27 . . . . . . .. 8 87 56 71 4 95 2O 64 2 2O 29 . . . . . . . . 9 87 58 72 96 20 64 2 21 29 . . . . . . .. 8 87 58 72 2 96 20 62 6 23 May 2 . . . . . . . . 9 87 5O 73 9 96 2O 65 24 2 . . . . . . .. 8 87 5O 74 4 96 2O 65 8 24 _ 2 . . . . . . .. 8 87 5O 74 4 96 2O 65 8 22 TEXAS AGRICULTURAL EXPERIMENT STATION. Table 3.—Duration of egg stage, brood—l9l7—continued. Temperature. Humidity. Laid. . Hatched. Days. _ Max. Mm. Mean. Max. Min. Mean. 1917 April 27 4 . . . . . . . . 7 87 50 73 3 96 24 66 1 . . . . . . .. l1 92 46 70 7 98 20 66 9 28 11 . . . . . . .. 13 92 46 67 1 98 22 66 4 May 1 15 . . . . . . .. 14 92 46 64 4 98 22 67 8 16 . . . . . . .. 15 92 46 64 6 98 18 66 7 6 18 . . . . . . .. 12 82 46 62 5 98 18 68 9 6 19 . . . . . . .. 13 82 46 63 4 98 18 69 1 11 21 . . . . . . .. l0 87 53 69 3 95 18 66 9 11 21 . . . . . . .. 10 87 53 69 3 95 18 66 9 13 22 . . . . . . .. 9 87 58 7O 8 95 18 65 9 15 23 . . . . . . .. 8 87 53 72 5 95 18 64 3 18 25 . . . . . . .. 7 87 55 74 3 95 32 66 7 18 26 . . . . . . .. 8 90 55 75 1 95 32 68 8 21 28 . . . . . . .. 7 91 55 ' 76 6 95 32 69 6 22 29 . . . . . . .. 7 91 55 76 4 95 20 63 8 23 9 . . . . . . . . 6 91 55 76 4 92 32 63 8 25 June 1 . . . . . . . . 7 94 57 79 95 2O 64 2 26 May 31 . . . . . . .. 5 91 57 77 6'_7 98 20 63 2 The longest period of this brood in 1917 was 15 days, with an aver- age mean temperature of 645° F .; the shortest was 7 days, with an average mean temperature of 7 6.4.° F. The average period of this brood was 11 days, With an average mean temperature of 723° F. Table 4.—-Period of incubation, spring brood. Mean temperature, Duration, Year. degrees F. days. 1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68.6 13.7 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68.9 9.0 1917 . . . . . . . . . . . . . . . . . . ..'. . . . . . . . . . . . 72.3 11.0 Table 4 gives the summary of the period of incubation of the Spring brood of M. Zzistrionica over the three years of observations. The rec- ords given show an average duration of this stage of 11.2 days, with a mean daily temperature of 699° F. Siam/m er Brood Q The period of incubation of the Summer brood is somewhat shorter than that of _the Spring brood on account of the great increase in the prevailing mean temperature. The length of this period is not as vari- able Within the season, or from ‘year to ‘Year, as is that of the Spring brood. (Original) [Blank Page in Original Bulletin] STUDIES ON THE HARLEQUIN BUG. 23 Table 5.——Duration of egg stage, brood—1915. - Temperature. Humidity. Laid. Hatched. Day?» _ Max. . Min. Mean. Max. Mm. Mean 1915 1915 June 19 June 24 . . . . . . .. 5 97 70 84 2 100 43 73 2 21 25 . . . . . . .. 4 97 7O 84 4 100 43 72 5 24 29 . . . . . . .. 5 98 74 86 100 32 71 9 26 July 1 . . . . . . .. 5 101 73 86 6 100 32 69 5 27 . . . . . . .. 5 101 73 86 8 100 32 67 3 30 6 . . . . . . .. 6 98 72 80 5 100 35 72 5 July 1 7 . . . . . . .. 6 98 7O 78 7 100 41 74 1 4 8.‘ . . . . . .. 4 95 70 81 8 100 51 75 3 6 11 . . . . . . .. 5 96 70 8O 5 100 44 7 4 8 13 . . . . . . .. 5 99 74 81 7 100 44 73 11 15 . . . . . . .. 4 99 73 82 4 100 39 71 3 13 18 . . . . . . . . 5 99 72 83 100 38 68 3 24 29 . . . . . . . . 5 99 63 ‘86.1 100 37 67 9 28 Aug 2 . . . . . . .. 4 102 71 87 99 37 69 3 The longest period of incubation of this brood was 6 days, with a mean daily temperature of 796° F.; the shortest period was 4 days, with a. mean daily temperature of 829° F. The average period for this brood for this ‘year was 4.8 days, with a mean daily temperature . of 83._a° F. Table 6.—~Duration of egg stage, brood—l916. _ Temperature. Humidity. La1d. Hatched. Days Max. Min. Mean’ Max. Min Mean 1916 1916 June 1 June 4 . . . . . . . . 3 95 73 83.6 98 46 69 2 8 . . . . . . . . 6 95 66 83.6 99 43 70. 1 2 9 . . . . . . .. 7 95 64 81.5 99 43 72.1 5 12 . . . . . . .. 7 95 64 79.7 99 43 73.1 3 17 . . . . . . .. 9 94 64 78.6 98 41 71.5 9 15 . . . . . . .. 6 94 65 81.1 98 41 70.4 12 18 . . . . . . .. 6 94 67 79.7 98 42 73.9 12 18 . . . . . . .. 6 94 67 79.7 98 42 73.9 ll 19 . . . . . . . . 7 95 67 80 98 42 73 .4 13 20 . . . . . . . . 7 95 67 79.7 98 38 72.5 16 2O . . . . . . .. 4 95 67 80.2 98 38 71.1 17 22 . . . . . . . . 5 97 69 82.6 98 38 69.7 18 24 . . . . . . . . 6 98 70 84.3 98 38 70‘.2 18 22 . . . . . . . . 4 97 7O 83.2 98 38 69 19 24 . . . . . . . . 5 98 70 85 98 38 7O 2O 25 . . . . . . . . 5 98 I 73 85.6 98 40 70.7 22 24 . . . . . . . . 2 98 ,_ 76 86.5 95 43 72.2 22 28 . . . . . . . . 6 99 74 86. 5 98 38 69. 5 23 27 . . . . . . . . 4 98 74 85.7 98 38 70. 6 24 28 . . . . . . . . 4 99 74 86.5 98 38 68. 1 24 29 . . . . . . . . 5 99 68 86.3 98 38 68.2 25 30 . . . . . . . . 5 99 68 85.2 98 39 68.1 25 3O . . . . . . . . 5 99 68 85.2 98 ' 39 68. 1 25 July 1 . . . . . . . . 6 99 68 84 98 39 68.4 28 4 . . . . . . .. 6 94 68 81.9 97 4O 73.1 29 5 . . . . . . . . 6 96 69 81 .7 97 44 74.8 3O 6 . . . . . . . . 6 96 69 82 97 44 74.2 3O 6 . . . . . . . . 6 96 69 82 97 44 74 July 3 8 . . . . . . . . 5 98 69 84 97 38 70.8 4 9 . . . . . . . . 5 101 69 85.4 97 37 67.3 4 9 . . . . . . .. 5 101 69 85.4 97 37 . 67.3 3 8 . . . . . . . . 5 98 69 84 97 38 70.8 5 10 . . . . . . .. 5 101 72 86 97 35 66.9 7 11 . . . . . . .. 4 101 72 87.4 97 27 63.5 9 14 . . . . . . . . 5 103 72 86.9 97 27 64.5 1O 15 . . . . . . . . 5 103 72 86.6 97 27 64. 7 11 16 . . . . . . . . 5 103 72 86 97 32 66.2 1 20 . . . . . . . . 6 102 73 86 97 33 66. 7 15 20 . . . . . . . . 5 102 73 87.3 97 33 66.8 15 21 . . . . . . .. 6 102 73 87.7 97 33 67.5 17 22 . . . . . . . . 5 102 74 88. 7 97 33 67. 5 18 22 . . . . . . . . 4 102 74 88.8 97 35 70.7 18 23 . . . . . . .. 5 102 74 87.9 98 35 71.4 19 24 . . . . . . .. 5 102 74 87.3 98 36 71.8 21 24 . . . . . . . . 3 102 74 86.2 98 37 73 24 TEXAS AGRICULTURAL EXPERIMENT STATION. Table 6.——Duration of egg stage, brood——1916—-continued. Temperature. Humidity. Laid. Hatched. Days. hdax hdin. hdean. hlax hA1n. hdean 1916 July 21 26 . . . . . . .. 5 102 74 86.2 98 34 69.4 22 27 . . . . . . .. 5 100 73 85.5 98 34 69.8 23 28 . . . . . . .. 5 100 73 85.6 98 34 70.2 25 31 . . . . . . .. 6 100 73 84.5 98 34 71.7 27 Aug. 1 . . . . . . .. 5 98 73 84 97 40 72.5 29 4 . . . . . . .. 6 99 73 83.4 99 37 69.1 31 4 . . . . . . .. 4 99 73 85.7 99 37 67.4 .Aug. 1_ 6 . . . . . . .. 5 99 73 88.2 99 37 67.6 1 7 . . . . . . .. 6 99 73 86.5 99 37 70.5 1 8 . . . . . . .. 7 99 73 86.1 99 37 70.8 2 7 . . . . . . .. 5 99 73 86.7 97 38 71.4 4 9 . . . . . . .. 5 98 73 85.6 97 40 73.4 5 10 . . . . . . .. 5 98 73 82.7 96 40 75.1 5 10 . . . . . . .. 5 98 73 82.7 96 40 75.1 8 13 . . . . . . .. 5 98 74 85.1 96 43 70.6 8 13 . . . . . . .. 5 98 74 85.1 96 43 70.6 8 14 . . . . . . .. 6 98 73 85.2 96 39 69.9 9 14 . . . . . . .. 5 98 73 85.2 96 39 69.9 11 17 . . . . . . .. 6 98 73 85.6 96 36 68.1 12 17 . . . . . . .. 5 98 73 89.8 96 36 67.3 14 19 . . . . . . .. 5 98 69 84.8 96 36 68.1 The longest period of incubation of this brood for this year was '7' days, with a mean daily temperature of 81.0° F.; the shortest period was 3 days, with a mean daily temperature of 862° F. The average period of this brood was days, with a mean daily temperature of 846° F. Table 7.——-Duration of egg stage, brood——1917. _ ~ Temperature. Humidity. Laid. Hatched. Days. hlax hdin. hdean. hlax h4h1 hlean 1917 191 hday 27 une 1 . . . . . . .. 5 94 57 62.2 95 20 62.6 28 2 . . . . . . .. 5 94 57 79 95 29 60.5 28 2 . . . . . . .. 5 94 57 79 95 29 60.5 29 3 . . . . . . .. 5 94 58 81.4 95 29 61.9 29 3 . . . . . . .. 5 94 58 81.4 95 29 61.9 31 5 . . . . . . .. 5 95 68 83.4 95 33 63.5 31 5 . . . . . . .. '5 95 68 83.4 95 33 63.5 June 1 6 . . . . . . .. 5 95 68 83.1 95 33 63.2 2 8 . . . . . . .. 6 95 68 62.8 95 33 63.4 3 9 . . . . . . .. 6 95 68 82.3 95 33 64.3 5 10 . . . . . . .. 5 95 72 83 98 36 64.5 7 12 . . . . . . .. 5 99 74 86.5 93 26 59.5 8 13 . . . . . . .. 5 100 74 87.2 93 26 60.7 8 13 . . . . . . .. 5 100 74 87.2 93 26 60.7 10 16 . . . . . . .. 6 ‘100 64 85.3 94 26 57.8 11 17 . . . . . . .. 6 100 61 83.7 94 19 54.8 11 17 . . . . . . .. 6 100 61 83.7 94 19 54.8 11 18 . . . . . . .. 7 100 61 82.2 94 19 53.4 11 18 . . . . . . .. 7 100 61 82.2 94 19 53.4 13 20 . . . . . . .. 7 100 60 79.3 94 19 52.1 13 20 . . . . . . .. 7 100 60 79.3 94 19 52.1 15 21 . . . . . . .. 6 96 60 76.5 95 19 50.2 17 22 . . . . . . .. 5 97 60 78.1 95 20 54.9 17 23 . . . . . . .. 6 99 60 79.3 95 20 55.5 19 24 . . . . . . .. 5 99 62 82.3 95 21 58.1 20 25 . . . . . . .. 5 99 63 83.8 95 21 59 21 26 . . . . . . .. 5 99 70 84.6 95 21 59.8 22 27 . . . . . . .. 5 99 70 83.9 94 21 60.5 22 28 . . . . . . .. 6 - 99 68 83.6 94 21 60.1 23 28 . . . . . . .. 5 94 63 83.8 95 21 59 24 29 . . . . . . .. 5 98 68 83.7 94 21 60.5 25 30 . . . . . . .. 5 98 68 83.4 94 _ 25 60.8 25 July 1 . . . . . . .. 6 100 68 87.3 94 25 60.3 27 2 . . . . . . .. 5 101 68 84.8 92 23 57.9 27 2 . . . . . . .. 5 101 68 84.8 92 23 57.9 28 3 . . . . . . .. 5 101 70 85.6 92 23 57.9 29 5 . . . . . . .. 6 101 70 85.2 95 23 57.9 30 5 . . . . . . .. 5 101 70 85.4 95 23 48.1 3m?» Plvfiwmam swam w. w=x=.=»m¢= wwcmwww. Zmncwmfl wmvwzsmfl. ncmwwawm w. vmnwmwocsa. AOAEEE [Blank Page in Original Bulletin] Srunrns ON THE HARLEQUIN BUG. 25 Table 7.——-Duration of egg stage, brood—-1917--continued. Temperature. Humidity. Laid. Hatched. Days _ _ Max. l\/I1n. Mean. Max. Min. Mean. 1917 July 1 6 . . . . . . .. 5 101 68 85.6 95 23 59 1 7 . . . . . . . . 6 101 68 86 95 23 59 3 3 8 . . . . . . . . 5 101 68 86.1 95 27 61 2 4 9 . . . . . . .. 5 101 68 85.9 95 27 61 9 4 9 . . . . . . .. 5 101 68 85.9 95 27 61 9 8 14 . . . . . . .. 6 108 71 91.9 93 23 55 5 8 14 . . . . . . .. 6 108 71 90.2 93 23 55 5 12 15 . . . . . . .. 3 108 73 90.8 94 24 59 8 14 18 . . . . . . .. 4 102 74 87.9 95 29 61 9 1 21 . . . . . . . . 7 102 69 87.3 95 29 63 3 28 Aug. 2 . . . . . . . . 5 99 43 82.5 97 23 63 5 31 6 . . . . . . .. 6 100 71 85 95 27 61 1 Aug. 1 8 . . . . . . .. 6 100 69 84.4 95 27 6O 7 The longest period of incubation of this brood for this year was '7 days, with a mean daily temperature of 820° F.; the shortest period of this brood was 3 days, with a mean daily temperature of 90.8° F. The average period of this brood was days, with a. mean daily tem- perature of 828° F. Table 8.——Duration of egg stage, summer brood. Mean _ Year. temperature, Duration, degrees. \ days. 1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.5 4 8 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.6 5 3 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.8 5 4 Table 8 gives a summary of the period of incubation of the Sum- mer brood of .14. histrionica over a period of three years. The records given show an average duration of this-stage of 5.2 days, with a mean daily temperature of 836° F. Fall Brood In the Fall brood we again have a long period of incubation and one which varies greatly, not only within the season but from year to year. The length 0t’ this period in the Fall brood is much the same as it is in the Spring brood. Table 9.—Duration of egg stage, brood——1915. Temperature. Humidity. Laid. Hatched. Days. Max. I Min. I Mean. Max. Min. Mean 1915 1915 Aug. 6 Aug. 15 . . . . . . .. 9 101 5 63 86.3 98 29 65.9 9 18 . . . . . . .. 9 100 63 83.1 98 29 66.4 22 27 . . . . . . .. 5 94 71.5 83.1 99 40.5 74.9 30 Sept. 4 . . . . . . .. 5 91 60 74.2 100 41 73.6 Nov. 5 Nov. 17 . . . . . . .. 12 92 33 71 100 25 77.6 5 21 . . . . . . .. 16 92 33 67.5 100 23 76.7 - 5 21 . . . . . . .. 16 92 33 67.5 100 23 76.7 5 21 . . . . . . .. 16 92 . 33 67.5 100 23 76.7 17 Dec 16 . . . . . . .. 29 84 31 58.2 100 14 67.1 , 26 TEXAS AGRICULTURAL EXPERIMENT STATION. The longest period of incubation of this brood was 29 days, with a mean daily temperature of 582° F. ; the shortest period of this brood was 5 days, with a mean dailv temperature of 786° F. The average period of this brood was 12.7 days, with a mean daily temperature of 740° F. Table l0.—Duration of egg stage, brood—l9l6. Temperature. Humidity. Laid. Hatched. Days. . - Max Min. Moan Max Min. Mean 1916 1916 Aug. 16 Aug. 21 . . . . . . .. 5 98 69 84.4 96 38 68.2 18 23 . . . . . . . . 5 101 72 85.4 97 29 66.1 23 i 28 . . . . . . . . 5 99 65 84.1 97 29 66.2 23 29 . . . . . . . . 6 99 65 81 . 7 97 29 67. 7 23 31 . . . . . . .. 8 99 65 84 98 29 - 68.1 25 8cpt. 3 . . . . . . . . 9 98 65 84.1 98 29 69.1 26 Aug. 31 . . . . . . . . 5 97 66. 85.5 98 29 65.8 26 Sept. 1 . . . . . . . . '6 77 66 84.6 98 29 66 29 3 . . . . . . . . 5 98 70 84.5 98 37 70.5 30 5 . . . . . . . . 6 100 70 84.7 97 34 66.8 31 6 . . . . . . .. 6 100 71 85.2 97 34 67.1 Sept. 9 Sept. 12 . . . . . . .. 3 95 72 84.5 97 35 69 11 15 . . . . . . .. 4 101 72 85.5 97 34 68 18 26 . . . . . . .. 8 96 61 8O 96 21 69.8 17 25 . . . . . . .. 8 95 61 78.6 96 21 57 i21 30 . . . . . . . . 9 96 51 79 96 21 63.7 21 30 . . . . . . . . 9 96 51 79 96 21 63. 7 17 25 . . . . . . . . 8 95 61 78.5 96 21 57 17 25 . . . . . . .. 8 95 61 78.5 96 21" 57 T17 25 . . . . . . .. 8 95 61 78.5 96 21 57 17 25 . . . . . . . .. 8 95 61 78.5 96 21 57 117 25 . . . . . . . . 8 95 61 78.5 96 21 57 '17 25 . . . . . . . . 8 95 61 78.5 96 21 57 17 25 . . . . . . .. 8 95 61 78.5 96 21 57 20 28 . . . . . . . . 8 96 61 79.5 96 21 64 20 28 . . . . . . . . 8 96 61 79.5 96 21 64 20 28 . . . . . . . . 8 96 61 79.5 96 21 64 2O 28 . . . . . . . . 8 96 61 79.5 96 21 64 20 28 . . . . . . . . 8 96 61 79.5 96 21 64 (by 1 Oct. 9 . . . . . . . . 8 95 46 76 97 20 61.8 6 13 . . . . . . .. 7 95 61 79.8 97 51 60.8 15 22 . . . . . . .. 7 92 38 68.8 99 31 70.1 lOct. 23 Nov. 6 . . . . . . .. 14 90 44 68 99 22 61.5 Nov. 3 20 . . . . . . . . 17 88 24 6O 105 25 67.3 The longest period of incubation of this brood was 17 days in 1916, with a mean daily temperature of 60.0° F.; the shortest period of this brood was 4 days, with a mean daily temperature of 85.5° F. The average period of this brood was 7.5 days, with a meanpdaily tempera- ture of 798° F. Table 11..—-Dlll'2lti0Il of egg stage, fall brood. Mean Year. temperature, Duration, degrees. days. 1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.0 12. 7 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . > 79. 8 7.5 l The average period of incubation of the Fall brood of M. histrionica, as obtained from our records, is given in table 11, a period of 10.1 _ days, with a mean daily temperature of 769° F. A A summary of the foregoing tables gives the following periods of in- cubation of M. hisirionica. A8 E35 wulg mmmm o» 25 wmzfina: 9.9 A5 v5.5a Maw" rwfinrma. nzammam Ho mam 5mm...“ A8 n32. .....Oct. 28 . . . . . . . . . . . . . . . . . . . . . .. 27 ‘Oct. 3 . . . . . . . . . . . . . . . . . . . . . . . . .. Oct. 18 . . . . . . . . . . . . . . . . . . . . . .. 15 Oct. 3 . . . . . . . . . . . . . . . . . . . . . . . . .. Nov. 5 . . . . . . . . . . . . . . . . . . . . . .. 33 Oct. 8 . . . . . . . . . . . . . . . . . . . . . . . . . Nov 15. . . . . . . . . . . . . . . . . . . . . .. 38 Oct. 1O . . . . . . . . . . . . . . . . . . . . . . . . .. Nov. 15 . . . . . . . . . . . . . . . . . . . . . .. 36 Oct. 12 . . . . . . . . . . . . . . . . . . . . . . . .. Nov. 15 . . . . . . . . . . . . . . . . . . . . . .. 34 The longest period of this brood was 38 days; the shortest was 15 ‘days, and the average period was 30 days. Proportion 0f Serves The proportion of sexes at different seasons of the year is interest- ing and throws some light on that part of the life history of the in- sect. On March '7, 1916, the harlequin bugs were coming from a woods. where they had hihernated, to a nearby collard patch. A collection of 805 laugs was made, of which. 344 ivere males and 4.58 were females This would seem to indicate that more females than males survived the winter. But it might be taken to indicate that the females left hiber- nation earlier in the spring' in_ search of food. During April, 1916. collections of bugs were made from the growing plants in the gardens, during the last ten days of the month. Of the 1'7 5 bugs collected during this period, 101 were males and seventy-four were females. The propor- tion of sexes at this time was the reverse of what it was when the bugs were first leaving hibernation. From May 25 to June 10, 1916, collec- tions were made from plants in the garden of the bugs. Of the 237 bugs collected, 150 were males and eightv-sexren were females. Again this is a preponderance of males, nearly twice as many. F'rom October 10 to 20, 1916, the bugs were collected from the plants in the garden, and in all, 113 bugs were taken, of which fifty-three were males and sixty were females. As "was the case upon leaving hibernation, there were more females than males at the time preceding the entrance into hiber- nation. In the over-wintering cages, 19] 5-1916, collections were made from time to time during December, January and February. Of the 141 bugs collected, seventy-two were males and sixty-nine were females. The bugs in these cages were collected in the Fall in the garden without regard to sex. From the above data it would appear that more females survived the winter than males, but that during the reproduction period of the year, the males are more abundant than the females. STUDIES ON THE HARLEQUIN BUG. A 37‘ DURATION OF LIFE CYCLE Over-urinterirtg Iirood Some bugs which had matured on October 9, 1915, were placed in cages, in pair-is, the cage being located in shelter. Of those that sur- vived the winter, one pair died, April 4, 1916; one pair on March 14,. 1916; one pair on March 16, 1916, and one pair on April 19, 1916. From these records the averslge adult life of the over-wintering brood was 171 days. Spring Brood On May 11, 1916, pairs of bugs that had just matured were placed in cages under natural conditions in the garden. One pair died July 16,1916; one pair July 25, 1916; one pair August 12, 1916, and one pair August 28, 1916. The records show that the average length of the adult’s life in this brood was eighty-six days. y On March 8, 1917, newly collected pairs of bugs were placed in cages» under natural conditions in the garden. One pair died on June 2, 1917; one pair on June 3; one pair on June 8; one pair on June 15.; one pair on June 25, and one pair on July 5. From these records, the average length of the adult life of the spring brood was ninety-seven days. The average length of the adult life of the Spring brood of 1916 and 1917 was 91.5 days. Smnmer Brood During the summer, 1915, the following records were made on the length of the adult life. One pair emerged July 25 and died on No- vember 15. One pair emerged July 27 and died November 21; one pair emerged August 8 and died November 9; one pair emerged August 9 and died October 18 ; and one pair emerged August 10 and died No’ vember 21. The average length of the adult life from these records- was ninety-nine days. During the Summer of 1916' the following records were made: One pair emerged May 18 and died July 9,; one pair emerged May 20 and died July 16; one p-air emerged May 24 and died July 20; one pair emerged May 28 and died July 20 ; andone pair emerged May 21 and’ died July 16. From these records, the average length of the adult life- of this brood was fiftyY-four days. . The average length of the adult life of summer broods of 1915 and 1916 was 76.5 days. The above data shows the following duration of the life of the adults: Over-wintering . . . . . . . . . . . . . . . . . . . . . ..171 days. Spring brood . . . . . . . . . . . . . . . . . . . . . . .. 91.5 days. Summer brood . . . . . . . . . . . . . . . . . . . . .. 76.5 days. NUMBER OF GENERATIONS As stated previously, the cage experiments that were conducted with the harlequin bug show that normally there are at College Station three 38 TEXAS AGRICULTURAL EXPERIMENT STATION. ewfiwuov aoiom flOUNu0iQU|.fi .w._m l-QI Kali-OI I ml F. DQD< lllllllllll f||||l|||||n|l|l| >< i ‘I'll STUDIES ON THE HARLEQUIN BUG. . 39 full generations a year. From the first born generation series it is evi- ’ dent that there is usually a partial fourth brood. By selecting the first born of each brood, it is possible t0 have the fourth brood about to ma- turity before low temperatures force the species to hibernation quarters. This fourth brood is to be disregarded at this latitude, however, as it must play an "unimportant part in the seasonal history of the pest and. the damage that may be done. Very few adults develop from the fourth brood and only adults can successfully pass through the winter at this latitude. In the southern part of the State there is. every reason to suppose that four complete generations occur in a. year. In the north- ern part of the State it is quite possible that only three complete gen- erations occur during the year. Figure 4 represents the data obtained from a generation study and shows the variation and overlapping in the broods. In this work the first born and last born individuals only were observed. The solid line represents the period from the time the egg was deposited until time for the following deposition, or the period of maturity of the bug. The broken line represents the period of’ egg deposition. The records of these series are given in this chart. On the first line is the adult over-wintering brood, the first eggs were laid on March 18 and the last eggs were laid May 25. The last batch of eggs resulted in mature bugs which laid their first batch of eggs on July 10. On the second line is _ the development of mature bugs from the first batch of eggs of the over-wintering- adults, and these laid their first batch of eggs May 21 and the last July 14. The adults from these had not developed when the work ceased. On the third line is the development of bugs from the first batch of eggs of the second generation and a part of their third period of oviposition. The chart gives an idea of the great variation in the development of this insect, as the three series were kept under the same conditions. Froni these records it is evident that for a short time eggs found in the fields may be of the last of the first generatio-n or the first of the second generation. Later in the season developing bugs mary be from the last of the first generation or the first of the second generation. Still later in the sea- son eggs may be those of the last born bugs of the first generation or of the first of the third generation. FEEDING HABITS During the spring the bugs feed extensively on the cruciferous plants with a preference shown for mustard.‘ On this plant the feeding is' confined to the young tender leaves that develop around the seed stalk. The most of the bugs are found on turnips, collards and kale. If seed stalks develop on any of these plants the bugs are found to concentrate on them, as in the case of mustard. In the experimental garden the mustard was killed by June 1 as a. result of the attacks of the harle- quin ‘bug. The bugs readily leave old plants for young tender growth, even the nymphs noticeably congregate on such plants. Cauliflower was not attacked when a good supply of collards was present. Rutabaga 40 TEXAS AGRICULTURAL EXPERIMENT STATION. turnips were not attacked until mustard was abandoned. Turnips do not show injury as quickly as mustard. Radishes are readily attacked and are not able to withstand the feeding of the bugs very long. With the beginning of summer, after the mustard, turnips and radishes have been killed, the bugs concentrate on kale and cauliflower. By July 10 all of the cruciferous plants in the garden were killed. Specimens of the harlequin bug were on pepper on two dates in June. In one case the nymphs as well as adults were present. No feeding was observed by either stage, so probably the insects were on this plant merely in their migration. Throughout June nymphs and adults were observed on okra but never have they been observed feeding. The first week in July, however, a noticeable injury was done to okra by the feeding of these bugs. Dur- ing June a single adult xvas taken from pumpkin and also one from egg plant. These were not feeding". During July, several bugs of all stages were found on cotton, especially around the developing bolls. The feed- ing punctures on the bolls are readily noticeable, and apparently were injurious to the boll. The adult bugs are known to feed on weeds in the absence of culti- vated plants. Usually the weeds a.re available at the time of year when the cultivated plants are not present, which time varies with the lo- cality in the State. ~ The comparative injury done by this insect in the spring or later in the year depends much on climate and localitv. The observations made- on this insect do not permit of a. general statement. Along the Gulf Ooast the crops suffer most from the attacks of the Spring brood, which is also the condition in the northern part of the State. In much of the remaining territory the later broods do the most of the injury. Whenever the host plants are available the harlequin bug feeds throughout the entire summer, but in some localities during the hot, dry portion of the year, green succulent plants are not always ‘avail- able. Except in the extreme southern port of the State the harlequin bug does not feed throughout the winter. The general feeding of the insect ceases with the occurrence of the first frost, which may be from September 15 to November 15. TENIPE RATUBF INFLUENCE The influence of low temperatures on the feeding habits of the har- lequin bug is interesting. The feeding of this insect during the spring " is of much importance from an economic standpoint. In the spring of 1915 some notes were made on the feeding activi- ties of the insect. On March '7 very few bugs were found feeding in the garden, but on March 12 the bugs were feeding on ra.dishes and mustard. At 3 p. m. the feeding was confined to the sunny side of the the plants. It suddenly turned cold on March 16, when but a single bug was found feeding in the garden. This was on mustard in a pro- tected place on the plant. ‘ On March 19 in an outdoor cage in the garden five bugs were in- active, while ten were huddled on the ground at the base of the plant. On the 19th in an outdoor cage the bugs were eatingfreely on mustard. STUDIES ON THE HARLEQUIN BUG. 41 From the 19th to the 22d wa.s a cool period, frost every night and ice two mornings. On the 22d the bugs were feeding‘ in the garden on mustard and also in the outdoor cage. On the following days the bugs Were feeding well down among the leaves. ‘From this time until the 30th the bugs fed freely, butt on the 31st no bugs were found feeding. The climatic conditions during this period are indicated in the fol- lowing table: Table 32.—Climatic conditions. Temperature. Humidity. _ _ Date. Precip. Char. DlI‘. Velo. Max. Min. Mean. Max. Min. Mean. Mar. 7 49 33 41 95 50 72.5 0 clear N 25 Mar. 8 40 33 36.5 82 63 72.5 0 cdy. N 15 Mar. 9 38 32 35 lOO 74 87 .12 cdy. E Mar. 1O 44 36 4O 95 63 79 .03 cdy. N 8 Mar. 11 56 34 45 96 47 71 5 O cdy. N 4 Mar. 12 62 46 54 86 5O 68 O P. C NE 4 Mar. 13 62 4O 51 98 41 69 5 O clear N 3 Mar. 14 7O 4O 55 99 37 68 O O clear S 2 Mar. 15 69 48 58.5 100 41 70 5 .10 clear NW 15 Mar. 16 56 36 46 85 43 64 O P. C. N 20 Mar. 17 53 35 44 99 5O 74 5 O cdy. N 8 Mar. 18 73 35 54 lOO 33 66 5 O clear S 2O Mar. 19 63 42 52.5 100 52 76 O P. C NW 20 Mar. 20 55 31 43 85 33 59 O clear N 15 Mar. 21 49 31 41.5 82 55.5 55 5 O clear N 25 Mar. 22 68 34 47.5 84 57 57 O . C W 15 Mar. 23 57 27 45.5 100 67 67 0 clear N 1O Mar. 24 73 34 55 9O 64.5 64 O clear S 25 Mar. 25 82 54 68 98 74 74 O P. C. S 2O Mar. 26 69 55 62 99 82 5 82 5 0 cdy. E 10 Mar. 27 58 46 52 99 83 83 O cdy. E Mar. 28 65 51 58 98 86 86 O cdy. S 2 Mar. 29 77 57 67 1OO 78.5 78.5 O P. C S 5 Mar. 3O 87 54 70.5 92 34 63 O clear W 5 Mar. 31 61 45 53 94 34 64 O P. C N I 25 Observations were made early in 1916 in outdoor cages and the bugs were active and feeding on the plants on January 2d, 13th, 20th; Feb- ruary 2d, 11th and 21st. l The climatic conditions existing on these dates were as follows: Temperature. Humidity. _ Date. Preclp. Char. Dir. Velo. Max. Min. Mean. Max. I Min. | Mean. Jan. 2 78 58 68 98 72 85 O cdy. S ' [10 Jan. 13 81 48 64.5 93 56 64.5 O clear N t" i 15 Jan. 2O 67 37 52 100 81 90.5 O cdy. S Q 15 Feb. 2 45 31 38 99 . 69 84 O cdy. N "qt 20 Feb. 11 75 57 66 100 54 77 0 cdy. S 1 5 Feb. 21 77 39 58 100 22 61 0 clear W Q? 5 The feeding activity of the harlequin bug during the different parts of the- (lay varies with the season. During the fall and, spring the feeding is confined entirely to the warmest part of the day, from 10 a. m. to 3 p. m. During the summer this portion of the day is avoided for feeding purposes, the hugs seeking places protected from the heat of the sun. LOCATION OF FOOD The adult bugs are able to locate food. in isolated places at any sea- son of the year. The greatest migration is in the spring upon leaving 42 Texas AGRICULTURAL EXPERIMENT STATION. the hiberating quarters. The bugs are attracted first to mustard, espe- cially rank growth which is usually too old for greens and consequently is seldom disturbed. In the fall collards are most-readily selected for feeding. For winter feeding the plants chosen are those in the most protected places, as close to a woodlot. A DAPTIVE CAPACITY In one instance the bugs were very numerous on a portion of a mus- tard bed that was not picked for greens in the spring. The growth of this mustard was very rank and served as ideal feeding quarters dur- ing early spring. Rather than feed on the mustard that was to be used for greens, the bugs spread to adjoining turnips when fresh feeding plants were needed. On these the ‘feeding was not general over the patch but confined to the area adjoining the rank growing mustard. On April 1-1 all of the mustard was cut. Twenty hours later fully seventy-five per cent of the bugs had sought new food. A few near-by stalks of volunteer mustard were severely attacked by the bugs and soon killed. Kale growing thirty feet away from the mustard attracted some bugs and a few went to turnips beyond the kale and sixty feet from the mustard. Cauliflower only fifteen feet from the mustard did not attract any of the bugs. The bugs remaining on mustard were con- gregated on a few partially cut otf stems. All of the bugs did not leave the mustard until thirty-six hours after it was cut, at which time it was badly dried. REPRODUCTION Uopulatiowz In the spring of 1915 bugs in the garden were observed in copula- tion for the first time on March '7. Again on the 22d, after a cool period, many of the bugs observed on the plants in the garden were in copulation. The next day but few pairs were observed, as was the case on the 30th. On the following day, however, many pairs again were observed in copulation. For the climatic conditions that prevailed dur- ing the month see table 32. Throughout April copulation may be ob- served at any time. In the spring of 1916 the first pair of copulating bugs were observed in the garden on January 20. In the outdoor cages copulation of the bugs was observed on January 11th, February 2d, 11, 21st, and March 1st. The latest dates of copulation noted in the fall of 1916 were No- vember 10th and 11th. - Period Between Zllaturity and Copulation In the season of 1916 more detailed notes were made in order to de- termine the age of the bugs when copulation begins. The results ob- tained from the spring brood are shown in the following table: STUDIES ON THE HARLEQUIN BUG. 43 Table 83.——-Period between maturity and copulation. {Cage no. Matured. Mated. First copulation. Period, days. A17 . . . . . . . . . . . . .. (3) May 14 . . . . .. May 15 . . . . . . . .. May 3O . . . . . . . .. 15 A18 . . . . . . . . . . . . .. (4) May 17 . . . . .. May 1 . . . . . . . .. May 31 . . . . . . . .. 20 A12 . . . . . . . . . . . . .. (l) Mar. 1 . _ . . .. Mar. . . . . . . . .. Mar 1O . . . . . . . .. 1O A15 . . . . . . . . . . . . .. (2) Mar. 5 . . . . .. Mar 6 . . . . . . . .. Mar 1 . . . . . . . .. 10 9 . . . . . . . . . . . . .. (5) May 17 . . . . .. May 19 . . . . . . . .. June 1 . . . . . . . .. 15 A20 . . . . . . . . . . . . .. (6) May 18 . . . . .. May 2 . . . . . . . .. June 1 . . . . . . . .. 14 From the above it would seem that from the time of maturity to the first copulation is not so long in the early part of the season as it is in the latter part oi’ the season. Copulatio-n took place soon after mat- ing in the one case when _mating was delayed. The average period from the maturity of the bugs to first copulation in the spring brood of 1916 was fourteen days. The results of the summer brood of 1916 are shown in the following table: - Table 34.—Period betweemmaturity and copulation. Cage N0. Matured. t Mated. Copulation. ‘Period, days. _ l 5 . . . . . . . . . . . . . ..May18 . . . . . . . ..May18 . . . . . . . ..May27 . . . . . . . .. 9 7 . . . . . . . . . . . . . ..May2O . . . . . . . ..May21 . . . . . . . ..May28 . . . . . . . .. 8 8 . . . . . . . . . . . . . ..May 31 . . . . . . . ...Iune 1 . . . . . . . ..June 2 . . . . . . . .. 3 . . . . . . . . . . . . . ..June .........June 3.........lunel0......... 8 10 . . . . . . . . . . . . . .. June 5 . . . . . . . .. June 6 . . . . . . . .. June . . . . . . . .. 5 With this brood the period is much shorter in the later part of the A season. The average period of this brood from maturity of the bugs to the first copulation Was 6.6 days. Table 35.—Fertility record of three females. Spring——1917. March. ApriL May. June. Date A B C A B C A B C A B C 1 . . . . . . . . . . . . . . . . . . . . . . .. E . . . . .. E E . . . . . . . . . . . . . . . . . . . . . . .. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . . . . . . .. E . . . . . . . . . . .. 3 . . . . . . . . . . . . . . . . .. E . . . . .. C . . . . . . . . . . . . . . . . . . . . . . .. E . . . . .. 4 . . . . . . . . . . . . . . . . .. C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 . . . . . . . . . . . . . . . . . _ . . . . .. E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E E E . . . . .. E E . . . . .. 7 . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . _ . . . . .. C . . . . . . . . . . . . . . . . . . . . . . .. 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 l . . . . . . . . . . . . . . . .. C . . . . . . . . . . .. C . . . . . . l . . . . . . . . . .. E . . . . .. 10 . . . . . . . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 E . . . . . . . . . . . . . . . . .. C E E . . . . .. E . . . . . . . . . . . . . . . . .. 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C C C . . . . . . . . . . . . . . . . .. 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. 14 . . . . .. E . . . . .. E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15 . . . . . . . . . . . . . . . . .. E E . . . . .. C E . . . . . . . . . . . . . . . . .. 16 . . . . . . . . . . . . . . . . . . . . . . .. C . . . . . . . . . . .. C C . . . . . . . . . . . . . . . . .. 17 E E . . . . .. E E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18 . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. E E C . . . . . . . . . . .. 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E . . . . .. C . . . . . . . . . . . . . . . . . . . . . . .. 20 . . . . . . . . . . . . . . . . . . . . . . .. E . . . . .. C . . . . . . . . . . .. E . . . . . . . . . . .. 21 _ . . . .. C . . . . .. E . . . . .. E . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. 22 E . . . . . . . . . . .. C C C E . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23 . . . . .. E . . . . .. C . . . . . . . . . . .. E E . . . . . . . . . . . . . . . . .. 24 . . . . . . . . . . . . . . . . .. E E E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25 E E E . . . . . . . . . . .. C C C C C . . . . . . . . . . .. 26 C C C . . . . . . . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. 27 . . . . .. E . . . . . . . . . . .. E E . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . .. 28 . . . . . . . . . . . . . . . . .. E E C E . . . . . . . . . . . . . . . . . . . . . . . . 4 . . . .. 29 . . . . .. E E C C . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. 30 E C C . . . . . . . . . . . . . . . . . . . . . . .. C . . . . . . . . . . . . . . . . . . . . . . .. 31 C . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. E . . . . . . . . . . . . . . . . . . . . . . .. E-—eggs. C—copulation . 44 V, TEXAS AGRICULTURAL EXPERIMENT STATION. Fert/ility The female can lay fertilized eggs for some time after the male is dead, although apparentljy copulation. takes place before each deposition. In many cases the female in the cages has laid. two or more hatches of eggs after the death of the male. In one cage the pair emerged May 10, were mated on May 13, the first eggs laid on June 2, and the male died June '7. . After this date the female laid fifteen batches of eggs. all of which hatched from June 8 to August 11. Tn table 35 are given the results of daily observations in three cages during the Spring of 1917. It is quite possible that all the periods of copulation werenot observed, although daily notes were made on the cages. lt may be said that generally copulation takes place soon after the batch of eggs has been laid and some time usually elapses between copulation and the deposition of the next batch of eggs. Oniposition The process of oviposition has been described in detail by Smith, and our observations only verify his description. The portion of the plant on which the eggs are laid may vary, but a protected place is always selected. The under sides of the leaves are chosen at all seasons of the ' year. Even in the late spring when the feeding is confined to the seed stalks of the host, the eggs are deposited on the more tender leaves of the main portion of the plant. Age at Beginning]. 0f Ovipositiotrz The age of the females when oviposition is started varies greatly with individuals, broods and seasons. No experiments were conducted to determine how long this could be made under adverse conditions. In nature all eggs deposited are fertile; in only a single case were infertile eggs laid. The over-wintering females began oviposition in 191.5 as early as March 13, and several b-atches of eggs were found in the garden on March 16. From that date the number of egg masses increased rapidly. The climatic conditions of this period are shown in table 32. On April 15, the mustard on which eggs were very abundant was cut. Most of the bugs then began feeding upon kale. In three days eggs were abund- ant on this host, and two days later the egg masses were more abundant on kale than they were on mustard, when it was cut. On the Summer brood of 1915 more detailed notes W's-re made on a few females to determine the age of the female when the first eggs were deposited. The results are shown in the following table: Table 36.——Age of female at beginning of egg deposition. Cage. Matured. First eggs. Period, days. Mean temperature. 1 . . . . . . . . . . . . . .. June 3 . . . . . . . . . June 16 . . . . . . . .. 13 82.1 2 . . . . . . . . . . . . . .. June 5 . . . . . . . .. June 23 . . . . . . . .. 18 82.8 3 . . . . . . . . . . . . . .. June 6 . . . . . . . . . June 20 . . . . . . . .. 14 82.8 4 . . . . . . . . . . . . . .. June 8 . . . . . . . . . June 22 . . . . . . . .. l4 83.2 5 . . . . . . . . . . . . . ..June 23 . . . . . . . ..July 20 . . . . 27 85.5 6 . . . . . . . . . . . . . ..June 24 . . . . . . . . . July 13 . . . . . . . .. 19 85.3 STUDIES ON THE HARLEQUIN BUG. 45 The average period for this hrood wras 17.5 days, with a mean daily temperature of 839° F. The observations made with the Fall brood of 1915 t0 ascertain the age of the female when the first eggs are deposited are given in the following table: Table 37.—Age of female at beginning of egg deposition. Cage. Matured. First egg. Period, days. Mean temperature. 8 . . . . . . . . . . . . . . .. July 27 . . . . . . . .. Aug. 6 . . . . . . . .. 10 85 5 9 . . . . . . . . . . . . . .. Aug 5 . . . . . . . .. Aug. 24 . . . . . . . .. 19 83 4 10 . . . . . . . . . . . . . .. Aug 9 . . . . . . . .. Aug. 24 . . . . . . . .. 15 82 3 11 . . . . . . . . . . . . . .. Aug . . . . . . . .. Aug. 24 . . . . . . . .. 15 82 3 12 . . . . . . . . . . . . . .. Aug 10 . . . . . . . .. Aug. 24 . . . . . . . .. 14 81 9 13 . . . . . . . . . . . . . .. Aug 12 . . . . . . . .. Aug 27 . . . . . . . .. 15 81 9 The average period of this brood was 14% days, with a mean daily temperature of 829° F. The period of the over-ivintering brood of 1915-16 as ob-served in cages are shown in table 3S. Table 38.—Age at beginning of egg deposition. Cage. Matured. First egg. Period, days. Mean ' temperature. 5 . . . . . . . . . . . . . .. Oct 10-15 . . . . .. Mar. 10-16 . . . . .. 152 t 60.6 6 . . . . . . . . . . . . . .. Oct 11-15 . . . . .. Mar. 6-1 . . . . . . 146 60.8 7 . . . . . . . . . . . . . .. Oct 13-15 . . . . .. Mar. 14-16 . . . . .. 152 60.3 8 . . . . . . . . . . . . . .. Oct 17-16 . . . . .. Mar. 6-16 . . . . .. 140 60.1 9 . . . . . . . . . . . . . .. Oct 15-15 . . . . .. Mar. 10-16 . . . . .. 146 60 5 10 . . . . . . . . . . . . . . . Oct 20-15 . . . . . . Mar. 15-16 . . . . . . 146 The average period of this brood was 147 days, with a‘ mean daily temperature of 604° F. The observations made on over-wintering brood of 1916-1917 for the period of the age of the females when the first eggs were deposited are shown in the following table: Table 39.—-Age at the beginning of egg deposition. F“ Cage. Matured. First egg. Period, days. Mean. ' temperature. A . . . . . . . . . . . . . . .. Oct. 10-15 . . . . . . Mar. 11-16 . . . . . . 152 60.9 B . . . . . . . . . . . . . . .. Oct. 15-15 . . . . .. Mar. 18-16 . . . . .. 156 59.9 C . . . . . . . . . . . . . . .. Oct. 20-15 . . . . . . Mar. 13-16 . . . . . . 144 59.9 D . . . . . . . . . . . . . . .. Oct 12-15 . . . . .. Mar 10-16. . . . p. 150 60.5 E . . . . . . . . . . . . . . .. Ort 17-15 . . . . .. Mar 15-16 . . . . .. 149 60.9 I The average period of this brood was 150.2 days, with a mean daily temperature of 60.4° F. The average period from maturity to oviposition of the brood of 1915-16 and 1916-17 was 148.6 days. The observations made in this period on the Spring brood of 1917 are given in the following table: a? 46 TEXAS AGRICULTURAL EXPERIMENT STATION. Table 40.—Age at beginning of egg deposition. I Cage. a Matured. First egg. Period, days. ’ t IVIGQItI . empera, ure. 17 . . . . . . . . . . . . . ..May11 . . . . . . . ..June ‘l . . . . . . . .. 21 77.9 18 . . . . . . . . . . . . . . . May 14 . . . . . . . . . May 31 . . . . . . . .. 17 77.1 19 . . . . . . . . . . . . . . . May 15 . . . . . . . .. May 30 . . . . . . . .. 15 76.5 20 . . . . . . . . . . . . . . . May 18 . . . . . . . .. May 28 . , . . . . . .. 10 76.7 21 . . . . . . . . . . . . . .. May . . . . . . . .. May 29 . . . . . . . .. 79.5 The average period of this brood was 14.6 days, with a mean daily temperature of 77.5° F. The average period between maturity of the bugs and egg deposition for the broods are as follows: Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14% days. Summer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17% days. Fall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13% days. Over-winter . . . . . . . . . . . . . . . . . . . . . . . .. 148% days. Period Between Copulation and Oviposition Usually a period of from two to eight days elapses between copula- tion and oviposition. This period varies with the brood, season and individual. _Table 35 shows the results of observations on this period of 1917. Usually copulation takes place the day following the deposi- tion of a batch of eggs. In the early spring copulation has been ob- served to take place twice after which a single batch of eggs was de- posited, twenty-one days later. Other cases were noted of seventeen and thirteen days between copulation and oviposition. Period of OUipOSI-iiofl In the ‘spring of 1915 the first eggs of the over-wintering brood were found in the field on March 13. The last of the eggs were deposited by this brood May 4. The extreme length of the ‘period was fifty-two days. The oviposition period of the Summer brood of 1915 is shown in the following table : Table 4I.——Period of oviposition. Summer brood—19l5. Cage. First eggs. Last eggs. Period, days. I . . . . . . . . . . . . . . . . . . .. lune 16 . . . . . . . . . . . .. ‘wept 1O . . . . . . . . . . . .. 86 2 . . . . . . . . . . . . . . . . . . .. Tune 22 . . . . . . . . . . . .. dept 15 . . . . . . . . . . . .. 85 3 . . . . . . . . . . . . . . . . . . . . lune 20 . . . . . . . . . . . . . Aug . . . . . . . . . . . . . 64 4 . . . . . . . . . . . . . . . . . . .. une 22 . . . . . . . . . . . .. dept 5 . . . . . . . . . . . .. 75 5 . . . . . . . . . . . . . . . . . . . . June 23 . . . . . . . . . . . .. Sept 1 . . . . . . . . . . . . . 7O 6 . . . . . . . . . . . . . . . . . . .. July 10 . . . . . . . . . . . .. Sept. 15 . . . . . . . . . . . .. 67 7 . . . . . . . . . . . . . . . . . . .. June 16 . . . . . . . . . . . .. Sept. 12 . . . . . . . . . . . .. 88 8 . . . . . . . . . . . . . . . . . . .. June 23‘ . . . . . . . . . . . .. Sept. 31 . . . . . . . . . . . .. 69 . The longest period of this brood was 88 days; the shortest was 66 days, and the average period of this brood was 75.5 days. STUDIES ON THE HARLEQUIN BUG. 47 For the Fall b-rood of 1915 the oviposition period is shown in the following table: Table 42.—Period of oviposition. Fall brood—-l9l5. Cage. First eggs. Last eggs. Period, days. 9 . . . . . . . . . . . . . . . . . . .. Aug. 6 . . . . . . . . . . . .. Oct 12 . . . . . . . . . . . .. 68 10 . . . . . . . . . . . . . . . . . . .. Aug. 23 . . . . . . . . . . .. Oct 3 . . . . . . . . . . . .. 41 11 . . . . . . . . . . . . . . . . . . .. Aug. 24 . . . . . . . . . . . .. Oct 3 . . . . . . . . . . . .. 40 12 . . . . . . . . . . . . . . . . . . .. Aug 24 . . . . . . . . . . . .. Sept 26 . . . . . . . . . . . .. 34 13 . . . . . . . . . . . . . . . . . . .. Aug 15 . . . . . . . . . . . .. §ept 2O . . . . . . . . . . . .. 36 14 . . . . . . . . . . . . . . . . . . .. Aug 20 . . . . . . . . . . . .. Sept 30 . . . . . . . . . . . .. 41 The longest period for this brood was 6'8 days; the shortest was 34 days. The average period of this brood was 43%; days. In the over-wintering brood of 1915-16 the oviposition period started in the cages as early as February 2, and the last eggs found in the cages were on May 23. In the field the first eggs were not taken until April 14 on mustard. During the fall of 1916 hatching eggs were taken from collards in the garden, on October 9, and again on October 23. Hatching eggs were taken from the cages on November 25 and 30. The period of oviposition in the Spring brood of 1917 is shown in the following table: ' Table 43_——Peflod of oviposition. Spring brood—1917. Cage. First eggs. Last eggs. Period, claysf‘! A . . . . . . . . . . . . . . . . . . .. Mar 14 . . . . . . . . . . . . . June 1O . . . . . . . . . . . .. 88 B . . . . . . . . . . . . . . . . . . .. ar 13 . . . . . . . . . . . .. June 9 . . . . . . . . . . . .. 88 C . . . . . . . . . . . . . . . . . . ..Mar 18 . . . . . . . . . . . ..May 25 . . . . . . . . . . . .. 68 D . . . . . . . . . . . . . . . . . . . .. ar 15 . . . . . . . . . . . ..May30 . . . . . . . . . . . .. 76 E . . . . . . . . . . . . . . . . . . .. Mar 2O . . . . . . . . . . . ..June . . . . . . . . . . . .. 8O The longest period of this brood was 88 days and the shortest period was 68 days. The average length of this period was 80 days. The period of oviposition in the Summer brood of 1917 is shown in the following table: ' Table 44.—Period of oviposition. Summer brood——l9l7. Cage. First eggs. Last eggs. Period. days. A . . . . . . . . . . . . . . . . . . .. May 29 . . . . . . . . . . . .. July . . . . . . . . . . . . . 42 B . . . . . . . . . . . . . . . . . . .. une 3 . . . . . . . . . . . . . July l4 . . . . . . . . . . . .. 41 C . . . . . . . . . . . . . . . . . . . . May 29 . . . . . . . . . . . . . July 14 . . . . . . . . . . . . . 56 D . . . . . . . . . . . . . . . . . . . . June 1 . . . . . . . . . . . .. July 10 . . . . . . . . . . . . . 4O E . . . . . . . . . . . . . . . . . . .. May 31 . . . . . . . . . . . .. July 15 . . . . . . . . . . . .. 46 The longest period of this brood. was 56 days and the shortest period was 40 days. The average period of oviposition of this brood was 45 days. The average period of oviposition of the Summer brood of 1915 and of 1917' was 60;} days. 48 TEXAS AGRICULTURAL EXPERIMENT STATION. ‘The ialilrlegifage period of oviposition of all broods is as follows; Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 days. Summer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60% days. Fall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40% days. Raise 0f Oviposition The rate of oviposition of the Summer brood of 1915 is shown in the following table: Table 45.—Rate of oviposition. Summer brood——l9l5. Cage. Eggs. Batches. Period. 1 . . . . . . . . . . . . . . . . . . . . 261 20 86 2 . . . . . . . . . . . . . . . . . . . . 138 14 85 3 . . . . . . . . . . . . . . . . . . . . 142 12 64 4 . . . . . . . . . . . . . . . . . . . . 89 9 75 5 . . . . . . . . . . . . . . . . . . . . 68 6 7O 6 . . . . . . . . . . . . _ . . . . . . . 79 7 67 For the Fall brood of 1915 the rate of oviposition is shown in the following table: Table 46.——Rate of oviposition. Fall brood--1915. Cage. _ Eggs. Batches. Period. . . . . . . . . . . . . . . . . . . . . 140 12 68 1O . . . . . . . . . . . . . . . . . . . . 116 1O l 41 11 . . . . . . . . . . . . . . . . . . . . 108 1O 4O 12 . . . . . . . . . . . . . . . . . . . . 82 34 The rate of oviposition in the Slaring brood of 1917 is shown in the following table: Table 47.—Rate of oviposition. Spring brood—1917. Cage. Eggs. Batches. Period. A . . . . . . . . . . . . . . . . . . . . 237 2O 88 B . . . . . . . . . . . . . . . . . . . . . 260 26 88 C . . . . . . . . . . . . . . . . . . . . 228 19 68 For the Summer brood of 1917 the rate of oviposition is shown in the following table: Table 48.—-Rate of oviposition. Summer brood—l9l7. Cage. Eggs. . Batches. Period. A . . . . . . . . . . . . . . . . . . . . 226 19 42 B . . . . . . . . . . . . . . . . . . . . . 116 14 41 C . . . . . . . . . . . . . . . . . . . . ~ 192 16 56 STUDIES ON THE HARLEQUIN BUG, 49 Generally more time elapses between dep-ositions of egg batches as the period of oviposition nears completion. Also the number of eggs in the batch decreases and irregular masses are more common near the end of oviposition period. The statement is usually made that nor-- mally the harlequin bug eggs are laid in regular batches of twelve‘ each, two rows of six each. The detail observation on the egg-laying record of the females of various b-roods are shown in the following: tables: Table 49.—Egg laying record. Summer brood——l915. 1 - 2 3 4 5 6 7 June 16 . . . . . . . . . . . .. 12 June22 . . . . . . . . . . . .. 12 12 i June23 . . . . . . . . . . . 12 r 12 i June25 . . . . . . . . . . . .. 12 June27 . . . . . . . . . .... 12 12 r 12 r June28 . . . . . . . . . 12 r June30 . . . . . . . . . . . 12 i 11 i July 1 . . . . . . . . . . . .. 12 i July 2 . . . . . . . . . . . 12 r July 4 ............ July 5 . . . . . . . . . . . -11 i July a . . . . . . . . . . . 12 i July 11 . . . . . . . . . . . ..'ii"'l" 11 i July 14 . . . . . . . . . . . ..1IiIiIiIIIIIIIII'i2"'l'II1IIIIIss....IIIIyIIII........ July 16 . . . . . . . . . . . .. 12 i 11 i July19 . . . . . . . . . . . .. 11 i 9 July 21 . . . . . . . . . . . HIIIIIII"a"i"io"1'“?"{'IIIIIIII................. July 22 . . . . . . . . . . . .. 12 r 7 i 11 i July 24 . . . . . . . . . . . ..IIfIIfII'io"'£'IIIIIIIIIIIIIIIIIIIIIIII'i2"'i"QIIIIIIIIi July 26 . . . . . . . . . . . ..12| i 12 i l July 2s . . . . . . . . . . . 12 r "8"?" July 30 . . . . . . . . . . . ..11 1 11 1 Aug. 1 . . . . . . . . . . . 12 r 12 i '11 i Aug. 2 . . . . . . . . . . . .. 1O r 6 i Aug. 3 . . . . . . . . . , . 11 r 89 Aug. 5 . . . . . . . . . . . 12 r 6 i Aug. 7 . . . . . . . . . . . .. 12 i 12 r Aug. 9 . . . . . . . . . . . 1O r 12 r Aug.11 . . . . . . . . . . . .. 12 l 12 i Aug.13 . . . . . . . . . . . 12 i 9 Aug.20 . . . . . . . . . . . .. 12 i Aug.27 . . . . . . . . . . . .. 12 i ........143 Aug.3l . . . . . . . . . . . .. 12 r 8 r i> c m: I-l v1 qoo *1 . June 5O Table 50.—Egg-laying record. Fall brood—l9l5. TEXAS AGRICULTURAL EXPERIMENT STATION. 9 10 11 b! l0 >->->->1 12 11 140 .......,.-,.I ‘d2. .. "12 12 r i2. ..r 12 r 12 i 116 12 12 108 ~1~4~CIIII ‘i2. .. :12. .. 82 Spring brood-—19l7. A - - . - . . . . . . . . . . . - . - . . . . . - . . . . . . . - . - . - . - . - . . . . . - . - . - - . - . - . - . - . - . - . - . - . - . . . . . . . - . - . - . - . - . - . - . . . . . - . . . . . . - . - . - . - . - . ¢ . - . - . - . . . . . . . - . - . . . - . - . - . - . - . .. . - . . . . . - . - . . . - - - . » . - . - . - . - . - . - . - . - . - . - . - . - . - . ¢ - .- - - . . . . . . . . . - . - . - . - . - . - . - . - . . . - . - . - . ¢ . - . - . - . - . - . .- - . - . - . - . - . - . - . - . . . - . - . . . . . - . ~ - - . - . . . - . - . - . - . _ -. - - . . . . . - . - . - . - - - . » . ~ . . . . . . . - . - . . . - . . . - . . . - . - . - . .. . . . . . . . . . - . - . - . - . - . . . - . . . . . . . - - - - - . - . - . - . - . - . . . .. . . . . . . . . . . . . . - . - . - . . . . . . . . . . . . - - . - . . . . . . . - . - - - . .. . . . . . . . - . - . . . . . . . . . - . . . . . . . . . . . - . . . . . . . - . - - - - - - .- . - . . . . . . . - . - . - . - . - . . . . . . . . . . . . . . . . . - . . . . - - . . . .- June 9 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. June 20.».................................IIIIIIIIIIIIIII 12 .. 12 i .i2...i.. 12' "15 IIII 11.1 .. 12' 12' "r" IIII If 10 h. 12 1 12' '1' .. 1O m. T10 15"?” 10 ‘d... 12' "F IIII II.I l0 wwi . >11 .->-,»-,-,I --I ::I1>-1I-": 12 12 h. .. h. .. .12. .. i2. .. 12 12 12 12 -'1>-1-'-"1'1:>-1>1.'-'-:-1 Srunrns 0N THE HARLEQUIN Bus. 51 Table 52.—Egg-laying record. Summer brood—1917. A May 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r May 28 . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r May 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r May 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1 June 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r June 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r June 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. June 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r June 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 i June 1O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 r June 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 i June 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. June 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. June 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 21 . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . June 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . June 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' . . . . . . . . . .1 June 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 i June 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . June 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r June 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . June 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. July 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . .. July 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ' July 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 r July 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. July 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1. . . . July_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1O y Ju!y12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . July 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PROTECTION Undoubtedly the egg is protected by- its location. Practically al- ways the eggs are deposited on the under side of leaves of the host. On mustard sometimes the eggs are placed on the seed stem, parallel to it. It is quite probable that the glue used in cementing the eggs to the host serves as a protection, at lea-st against severe climatic condi- tions. The striking color pattern of the egg is not so noticeable on the hosts as may be expected. After hatching, the young nymphs feed in groups, usually very close to the egg mass. In this way, the young are not easily distinguished from the eggs, as shown in plate 5 (b), except at the time of the moults when the shell of the nymph is quite hard. The feeding of the nymphs is irsu-ally on the under side of the leaves in more or less protected places. If the plant is much disturbed, some of the young fall to the ground, the very young feign death, butthe older nymphs seek shelter. It has been said that the gay colored pattern of this in- sect serves as a protection in the form of warning. If such is the case, the bugs must have a disagreeable taste. The adults are protected chiefly by their color pattern, which serves as a warning to predacious enemies. In handling the bugs, they do not emit any odor which could be detected. Their shell is very hard and this may make them very undesirable as food to pillagers. 52 TEXAS AGRICULTURAL EXPERIMENT STATION. HIBERNATION Entrance The time of the entrance into hibernation by the bugs depends en- tirely on the temperature. Food is usually present in abundance over most of the State and the bugs continue t0 feed until the low tem- peratures force them to seek shelter. Until November 8, 1916, the bugs Were numerous and active 0n the collards in the garden. During the preceding night the temperature dropped to 51° F., and there was .38 of an inch rainfall. On the following day, very few bugs could be found on the plants in the garden, even though the temperature had greatly increased during the afternoon. Examinations showed that many bugs were in bunches of grass close to the collards. It was ap- parent that the bugs were slow to leave this temporary shelter to resume their feeding. On the night of the 12th, the temperature. was 31° F., and 34° F‘. the following night. On the 14th not a single bug could be found 0n the plants in the garden. Following these temperatures there was a week of warm weather but several days elapsed before many bugs ventured. out to feed again. On the morning of November 1'7, nearly all of the bugs were found in the rubbish. around the base of the plants. A few were on the stem of the plant very near the ground, although they were not feeding. The air above the ground seemed to be warmer than farther up on the plant, which may account for the fact that a few bugs did not seek shelter and none of these bugs made an effort to escape when picked up. On the following day, no bugs were found on the plants, as the» temperature of the preceding night was 36° F. During the afternoon many bugs were active on the plants, though many still remained in rubbish about the base. The following day was much warmer and many bugs were present on the plants. Some of these were feeding” and one pair was observed in copulation. On November 23 a few bugs were observed on the sunny side of the plants. They were inactive and were not feeding. The following day was slightly cooler and no bugs were found on the plants, but were in the rubbish at the bottom. The following night the temperature was 35° F‘. and the next morning no bugs were on the plants. Many were found on bunches of grass adjoining the garden. It was not possible at any time to find in shelter close to the garden as many bugs as it was possible to find on the plants during the warm period. The additional bugs might have sought more permanent shelter in the adjoining woods, shown in plate 5. The en- trance into hibernation should be considered gradual. Stages Entering Only adult bugs enter hibernation. The nymphs may survive late in» the fall, as long as they can withstand temperatures in temporary pro- tection in the field, but they cannot leave the field for permanent hiber- nation quarters. On November 16, nymphs of the last instar were taken on plants in the garden. They did not mature before cold weather killed them. At this time, the bugs on the collards were about Sruorns ON THE HARLEQUIN Bus. 53 equal in numbers of males and females. A week later, however, only females were observed 0n the plants. They were inactive and Werenot feeding. i ' Congregation Before Hibernation During the late fall the bugs seemed to’ congregate on the host plants before going into hibernation. The approach of cold weather forces the bugs to seek feeding which is close t0 permanent shelter. During the warmer part of the days, the bugs are very active, many are inithe air, those on the plants take flight when disturbed and any that fall to the ground immediately attempt to escape. Much time is spent in feeding. Zli/ortolity There is some mortality among the bugs at the time of entering hibernation. The great majority of the bugs that die at this time are undoubtedly the very old adults of. the summer generation. Their vitality is low and the cold nights are enough to cause death. Sudden cold spells may kill a number of over-wintering bugs before actual hibernation takes place. However, the bugs seem to be able to fore- tell what temperatures are probable and seek shelter if necessary. Duration At this latitude there is not a true hibernation, for if the weather is ‘sufficiently warm at any time during the winter the bugs will leave hibernation. The last week of November, 1916, was warm after the bugs had left the fields. During this time a few bugs returned to the plants although they did not feed, but the great majority remained in hibernation. The maximum temperature for this period was 81° F., the minimum temperature for this period wvas 52° F., and the mean daily temperature was 65° F. - The first. week of December was warmer, the maximum was 80° F., the- minimum was 50° F., and the mean daily temperature was 70° F. Morebugs were present on the plants and were feeding. At such a time the bugs leave the plants every night for temporary shelter. The three weeks of December were cold, and no bugs were found on the plants in the. garden. During this period the maximum temperature was 82° F., the minimum was 20° F., and the daily mean temperature 50° F. After the first week of this period no bugs were found in the temporary shelter closef to the plants. The bugs were again active during the first four days of January, 1917, with a daily mean temperature of 72° F. On thefollo-wing night a frost occurred and the bugs were not seen on the plants when the mean daily temperature was 57° F. or above. Below this temperature the bugs remained in their shelter. The last three days in January were warm, a mean daily temperature of 67° F., and the bugs were quite active on. the plants, though feeding very little. No bugs were noticed on February 8, with a mean daily temperature of 511° F. The mean daily temperature ranged from 60" F. to 69° F., and. the bugs were quite numerous in the garden, very often feeding. 54 TEXAS AGRICULTURAL EXPERIMENT STATION. Shelter Favorable shelter conditions are absolutely necessary to the success- ful hibernation of the harlequin bug. If good shelter is close to good feeding, the chances of successful hibernation are much increased. In this locality, the bugs usually leave their hibernating quarters and feed during the warm periods throughout the winter, especially when food is near. The garden was bounded by a few rows of Sudan grass and only a short distanceaway, perhap-s 150 feet, was a. wooded ravine, shown in plate 5. The Sudan grass served as an excellent temporary shelter. During the early fall when the cold spells prevailed the bugs were found in numbers in clumps of the grass. In a few cases, as many as twelve bugs were counted from one small clump. The bugs did not merely’ crawl down into the crown of the grass, but were found in among the roots. Any plant rubbish, such as fallen leaves, about the base of the plants serves as a temporary shelter and in the southern part of the State is sufficient protection for‘ the insect throughout the entire winter months. In this locality, even with a. minimum temperature of 28° F, in the early fall the ‘ougs will only seek temporary shelter. No mortality was observed tinder. these conditions. As the season advances the low tem- peratures may occur, and each night fewer bugs are found in the tem- poraryr shelter in and close to the field. On December 9, 1916, the bugs were to be found in considerable numbers in the clumps of grass and they were rather active when disturbed. A few days later, after a few nights of fro-st, only a few bugs could be‘ found in the grass and a week later no bugs were present. During the winter after the warm spells the bugs could be found in temporary shelter for a day or two after low temperatures a.gain prevailed. In one instance, on Decem- ber 1'7, 1916', twenty bugs were found under some oak leaves that had accumulated in front of a fence post. In late winter bugs were taken from temporary shelter in the collard patch where they apparently had survived during the winter. A One experiment was conducted to show the importance of shelter and feed to the successful hibernation of the harlequin bug. On No- vember 10, 1916, a warm day when the bugs were active, five males and five females were placed in a cage without any food or shelter. Three days later, after a cold night, three females were found dead. The fol- lowing day, after a night of 30° F, one male was dead; the remaining . insects were on the side of the cage. On December 6, the remainder of the bugs in the cage were dead. The same number of bugs were placed in a cage with plenty of food and shelter. During the cold periods no bugs were teen on the side of the cage, as were bugs without shelter. During the warm weather the bugs were always feeding. All of these survived the winter. The matter of shelter depends on the locality of the State. Through- out the southern section the bugs seldom seek shelter during the win- ter. Further north temporary shelter is always sought and permanent‘ shelter is used but for a short time. Throughout the northern section the bugs leave the fields a.nd seek protection in timber, buildings and trash. t . STUDIES ON THE HARLEQUIN BUG. 55 Mortality _ individuals of the harlequin bug. On January 20, 1917, further field ' examination showed 25 per cent. mortality. On March, 3, 1915, ex- ’ amination in outdoor cages showed 33% per cent. mortality. Another . examination of the outdoor cages on March 16, 1915, revealed 16% per ‘ cent. mortality. ‘ » Table 53.—-Mortality of the harlequin bug in outdoor cages. In this locality there is a considerable mortality in overl-xvintering ‘ l | l Cage no... . N0. 1 No. 6 l No. 7 No.9 N0. 11 No. 12lN0. 13 N0. 15 N0. 17 N0. 22 Total. No. in cage 150 150 1 150 100' 150 100 100 150 100 100 i- Nov. 17-15 5 2O 5 0 6 5 5 20 3 13 82 Dec. 1-15 24 6 9 2 12 2 O 4 3 O 62 Dec. 20-15 4 3 4 O . . . . .. O 0 . . . . . . O . . . . . . 11 Dec. 4-15 1 1 3 O 4 O O 4 O O 13 Dec. 31-15 2 3 3 O O 1 O 1 O 0 1O Jan. 7-16 4 0 2 1 4 3 1 O O 0 15 _ Feb. 11-16 7 6 3 10 4 1 1 7 9 0 48 ._ Feb. 21-16 0 0 2 1 O 0 0 O 0 O D3 ' Mar. 13-16 0 O 0 3 17 _ 0 0 0 0 0 20 ' Total died. . 47 39 31 17 47 12 7 36 15 14 264 .‘ Percent 1 t died..... .31 .26 .21 .17 .31 12! .07 .24 .15 .14 .21 ‘In table 53 is given the mortality record of our outdoor cages for i the winter of 1916-17. The maximum mortality was 31 per cent. ; the g minimum was 71.2 per cent, and the average mortality was 22 per cent. '- It will be seen that a very heavy mortality occurs in late fall and early A winter and againin late winter or early spring, the time when sudden cold spells occur. l E-nzergence g The time of emergence from hibernation of the harlequin bug in this A, locality is hard to determine because of the intermittent winter feed- s ing. Many of the bugs do not truly hibernate in this latitude. On 3 March 1, 1916, many bugs xvere found on the outside of the outdoor _ cages, ap-parentlyseeking the food on the inside. These bugs appar- ently had come from an adjoining woods. A week later hundreds of *3 bugs were congregated around the outdoor cages. fisixty of which were females. In the afternoon of the following day, an isolated collard patch which was surrounded by woods was visited. Here it was found that the bugs were coming from the woods on the north against a fifteen- Lmile-per-hour wind. The bugs could be seen in the air as far as 115 i_ yards, flying to a. height of about ten feet, although some were flying i as low as five feet. The woods to the north was 200 yards away. An :inspection'of the border of the woods did not reveal the ‘presence of a =single bug. 1t was then evident that the brugs were coming from farther in the woods and examinations were made which revealed. bugs in the cracks of the bark on the trunks of the larger trees. These hugs took flight upon the least disturbance. A collection of 700 bugs was Imade in the garden, 305 of which were males and 395 of- which were A collection was made of 100 bugs, forty of which were males and i 56 TEXAS AGRICULTURAL EXPERIMENT STATION. females. The next day the same collard patch; was visited. This time the wind was from the north and it was cooler. No bugs were in the air and those on the plants were much less active. In the spring of 1917 the bugs left hibernation. much earlier than in 1915. On February 21, 1917, the bugs were very abundant in the garden, very active,_and flying if slightly disturbed. All of the bugs ' were feeding and some were copulating. Wherever hibernation takes place in the State the emergence occurs from February 15 in the south to April 15 in the extreme northern pea-rt of the State. - Rehibernation After the bugs halve left their prermanent winter quarters they are often forced t0 seek temporary shelter during the sudden cold spells in the early spring. On March '7, 1915, most of the bugs were found in the rubbish close to the plants. The day was cool and clear with a hard north Wind blowing. Following this, the bugs were active for a week, when they were again forced to seek temporary shelter. They were inactive for several days while the cold Weather persisted. As late as March 30, 1915, the bugs were found in temporary shelter during a cold spell when the temperature Went as low as 45° Ff The hibernation period of the 1916 brood was from December 1, 1916, to February 21, 1917. First Food The first food of the harlequin bug is very largely a. matter of avail-- able host plants. In this locality where two or three host plants are present, there is apparently some choice. Mustard is preferred in the sp-ring, although other host plants may be present in the same garden. Radishes are often attacked early in the spring. If mustard is not avail- able, turnips seem' to be the next choice. In many other localities, cabbage is attacked early in the spring, as it is the only available host. The individuals of the over-wintering" brood usually mature from September 1 to October 1 and live until April 10 to 20 of the follow- i ing spring. The bugs are very active in the field for a period before oviposition, rvhich time is spent in feeding. NATURAL CONTROL CLIMATE Climate is a natural control measure of m.uch importance with the harlequin bug. The extreme heat prevalent through the summer serves i as a considerable check on this pest. The eggs are always deposited on the under sides of the leaves at this season. By experiments conducted during July, 1915, it was found that an exposure of the eggs to the direct rays of the sun for a. period of ten minutes would kill them. The results of these experiments are given in table 54. Srunrns ON rm: HARLEQUIN BUG. 57 Table 54.—-Effect of heat on the eggs of the harlequin bug. Heat, degrees F. I Exposure. Effect. 104 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ' 5 minutes Hatched 116 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 minutes Hatched 116 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1O minutes Killed 116 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 minutes Hatched p118 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 minutes Hatched 120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1O minutes ' Killed p The elfectof cold on the adults has already been mentioned under " the mortality of hibernated individuals. The nymphs are not able to survive much cold. In the second instar the temperature of 40° F. is . fatal. 'l.‘he nymphs of the fourth instar do not succumb until a tem- Q perature of 32° F. is reached. ' i; Excessive rains kill both nymphs and adults. On April 23, 1915, 5,, a rainfall was 2.95 inches; on April 24, 1 inch; on April 25, .47 inch; 5,‘ and on April 26, .08 inch. The total rainfall of four days was 4.5 .2] inches. After the rain, many dead adult bugs were found. These were found mostly on the ground, but some Were in the axils of "the leaves. rOn December 8, 1915, many nymphs in several outdoor cages were ‘drowned, although the adults survived this storm, when 2.415 inches o 5 Train fell. ‘ PARASITES has been found during the observations of over three years in this _lo- f. cality. In 1892 Morgan found a parasite of the egg of the harlequin ' bug to be very common in Louisiana and Mississippi, a.nd‘ this was de- iqtermined as Trissoleus murgantiate Ashm. Attempts were made to es- iltablishp this parasite in other States, but apparently without avail. Mor- iygan also records the parasite, T. podisi, reared from the eggs of the harlequin bug. ‘ ' y ENEMIES “In June, 1916, several of the rearing cages were visited by the fire . ant, Solenopsis gemimzta Fab. The freshly emerged. nymphs were car- jiried off by the ants but no other stage was molested. This is the only case of predacious enemies observed in our work. Lintner records aLeptoglosnsus phy/clopu; Linn destroying the adult harlequin bug. Poul- ftry, turkeys, geese, and ducks will not eat the harlequin bug in any stage. ARTIFICIAL CONTROL FALL DESTRUCTION _. It is often a simple matter to destroy large numbers of bugs during ‘the fall. At ‘this time, they are congrelgating about the remains of ‘crops and weeds, feeding some and preparing to go into hibernation. iAt such times the bugs may be killed by hand picking, spraying or burning. Trap- shelters» are not satisfactorily efficient. Their use re- "uires peculiar attention such as would seldom be given under field lnditions. Just before hibernation the bugs frequent any shelter avail- No evidence of a parasite of any of the stages of the harlequin bug " 58 ’ TEXAS AGRICULTURAL EXPERIMENT STATION. able in the field. During the "morning the bugs can be collected fron such places in very large numbers. The same conditions exist in thi early spring when the bugs are forced to seek protection every night All bugs killed during the fall will mean that many less to fight the . next spring when they will be scattered over the plants. The work p-u1 in at this time will prove to be an essential part in the fight against this pest. i WINTER TREATMENT As the bugs hibernate mostly in the fields Where they feed, especially during the fall, it is apparent that all the excess plant growth in and around the field should be destroyed. The remains of the last crop should he disposed of by plowing under or burning. When such ma- terial is destroyed the hibernating quarters of the bugs are gone. With such treatment the chances are much less for the insect to survive the winter. The weeds and trash around and close to the fields should be disposed of in some manner. Rank Weeds should not be allowed tc grow during the late fall, since they serve as protection to the bugs. SPRING TREATMENT It is very important in the fight against this pest to destroy the bugs early in the spring as they are leaving the hibernating quarters. This should not be delayed until egg laying has commenced. Several days elapse between the time the bugs come out in the spring and the be- ginning of egg laying. r CLEAN CULTURE There are several common Weeds on which this insect breeds during the early spring. They are named under the food plants. Such weeds should be kept down at all times, not only in the fields to be planted to cabbage, but in adjoining fields and specially waste places. Weeds of any kind should not be tolerated at anv time upon any farm, as they serve in one way or another to keep up the supply of insect pests. TRAP CROPS Trap‘ crops are those planted at such a time that they will prove attractive to a pest before and after the main crop-. If well handled, a trap crop may be a very big factor in the control of the insect; if not properly handled, it simply serves ‘as an aid t0 the pest. Mustard is perhaps the best trap crop to use for the harlequin cabbage bug, though turnip, kale, or cabbage may be used. These crops should be planted at such a time that they will be attractive to the insects during the spring, from the time the hugs leave their hibernating quarters until the egg lay- ing period isover. When the bugs become very abundant on the trap crop they should be destroyed either bv spraying with pure kerosene, burn- ing, or destroying the trap crop. During the fall the trap crop may be used to a decided advantage. Tt should be planted so as to be attrac- tive to the insects after the main crop has been harvested before the bugs seek hibernating quarters. The harlequin bug is not attracted to Srunrns ON THE HARLEQUIN BUG. 59 sweetened mixtures and the use 0t such compounds with poison is of no practical value Whatever. The same may be said of the trap lights. Records of insects caught around trap lights do not show the presence of a single harlequin bug. REMEDIAL MEASURES HAND PIOKING If the preventive measures have been carefully followed, the number of bugs that will appear during the summer has been materially re- duced. But in sp-ite of some precautions some bugs will be present to do injury to the crops. Whenthe bugs first appear on cabbage, hand p-icking is perhaps the most satisfactory means of fighting the pest. Here again, the habit of the insect of not flying readily, is decidedly in favor of those attempting to clean "their fields by such a method. Reinfestation is not likely to occur. This process may appear to be ex- pensive and tedious, but by those who have used it it is considered a satisfactory step in the fight against the pest. SPRAYING The spraying is not entirely satisfactory” for the control of this in- sect. Any material now known to kill the bugs will also kill the plants upon which they are feeding. Kerosene is most used for spraying against the bugs. It is very effective when sprayed undiluted but of course kills the plants. The best time to use this material is in the destruction of the insects on a trap crop and upon crop remnants. Kerosene emulsion of 15 per cent. strength may be used to kill the young or immature bugs." L. B. Smith reports 65 to '75 per cent. mortality of the nymphs and 45 to 50 per cent. of the adults with thefollowing mixtures: Nicotine sulphate, 4Q per cent. . . i. . . . 6% ozs. Fish oil soap . . . . . . . . . . . . . . . . . . . . . . .. 8 lbs. Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50 gallons. In order to obtain good results, this material must be applied under a pressure of from 1'75 to 200 pounds. The harlequin bug feeds by sticking the juices of the plant, and can- not be controlled by the use of arsenical sprays, such as Paris green, London purple, and arsenate of lead. Contact sprays must be used, which means that if a bug is not hit with some of the material it is in no way injured by the application. Some persons have found the plumber’s torch to be very effective in the destruction of these bugs upon trap crops and trap remnants. Undenthese conditions such i treatment may be advisable, but the use of the torch is somewhat . limited. 6O TEXAS AGRICULTURAL EXPERIMjENT STATION. ~ SUMMARY The harlequin bug is found over the entire State of Texas. It is ‘injurious to many garden and truck crops, including cabbage, cauli- flower, collard, mustard and turnip. The egg stage of the Spring brood was found to be 11.2 days, of the Summer brood 5.2 dalvs, of the Fall brood 1.01 days. The period of maturity of the Spring brood was 4613 days, of the Summer brood 30.9 days, of the Fall brood 35.6 days. The length of the adult life of the Spring brood was 91.5 days, of the Summer brood 87.7 days, and of the over-ivintering brood 171.0 days. At College Station there are three complete generations of the har- lequin bug in a year, with a partial fourth brood. There was an aver- age mortality of hibernating bugs at College Station of 22 per cent. There were no parasites or predacious enemies observed that are of economic importance. Artificial control must be used against this pest. Such measures as fall destruction, winter treatment, spring destruc- tion and clea11 culture must be used. Remedial measures consist of hand picking, and spraying. LI TERATUItE CITED (1) 183-1. Hahn, Wanzenartigen Insecten, II, p. 1'16, fig. 193. Original description with distribution. ('2) 1851. Dallas, List ot‘ Hemiptera, I, p. 263, records this species from the British Museum. - (3) 1.866. Walsh, Benj. J. The Texas Cabbage Bug. Practical Entomologist, August .27, 1866, gives account of Dr. Lincecum; first record of occurrence in United States. (4) 1870. Itiley, C. V. The Harlequin Cabbage Bug. The Amer- ican Entomologist, January, 1870, records the presence from North Carolina. (5) 1870. Stel.le, J. P. Southern Notes. The American Ento- mologist, March, 1870, p. 154, records the presence in Georgia, Ala- bama and Mississippi. (6) 1870. Stelle, J. P. Southern Notes. The American Ento- mologist, March, 1870, describes spread through Alabama. (7) 187]. Stal, C. Enumeratio Hemipterorum, II, p. 37. Speci- mens from Mexico in Stockholm Museum. (8) 1872. Rilev, C. V. The Harlequin Cabbage Bug, Fourth Re- port State Entomologist, p. 35, records presence in Kansas and Mis- souri; general review of literature. (9) 1875. Uhler, P. H. Geological Survey of Territories, p. 396, records presence in Colorado. (10) 1880. Godman & Salvin. Biologia Centralia-Americana. Rhynchota I, p. 71. Complete account. (11) 1882. Lintner, J. A. Injurious Hemipterous Insects. First' Report Injurious Insects, New York, p. 264. Complete account. (12) 1899. Webster, F. M. Insects of the year in Ohio. Bur. Ent. Bul. 20, us, p. 71. Effect of low temperatures on distribution. STUDIES ON THE HARLEQUIN BUG. r 61 (13) 1901. Webster, F. M. Insects of the year in Ohio. Bur. fint. Bul. 31, n.s., p. 87. Present again in Ohio. (14) 1908. Sanderson, E. D. The Influence of Minimum Tem- )eratures on Limiting‘ the Northern Distribution of Insects. Jr. Eco. Ent. I, 4, p. 245. The species so restricted. I BIBLIOGRAPHY ktkinson, J. F. 1888. The Harlequin Cabbage Bug. S. C. Bul. No. 2, part 1, page 176. Bul. N0. 4 (new series), p. 57. Record of first occurrence. - Barre & Conradi. 1909. Treatment of Plant Diseases and Injurious Insects in South Carolina. S. C. Bul. 141, p. 28, 1909. Trap crops advocated. Spray with kerosene. Burn plant and bugs. Beckwith, M. H. 1891.. Injurious Insects and Insecticides. Del. Bul. 12, 1891, p. 11. Suggestions as to remedies. Bennett, E. B. 1909. Cabbage-Growing on the Irrigated Land of Colorado. Col. Bul. 143, p. 7. Found in only a few localities, contact insecticides ineffective. Bethune, 1871. Rcpt. Ent. Soc. Ontario for 1871 (1872), p. 87. Britten, W. 1914. Miscellaneous Insect Notes. Conn. State. Be- port, 1914, p. 193. Specimen taken at Meridian, Conn, on July 4, 1910. Only record of occurrence in State. Campbell, J. P. 1889. The Harlequin Cabbage Bug. GasBul. No ' 3, p. 47. Popular account with remedies. Chandler, W. H. 1912. Spraying Cabbage, Cauliflower, Kale, etc. Mo. Bul. No. 102, p. 269. Popular description with general life history. Trap crop and spraying suggested. Chittenden, F. H. 1900. Miscellaneous Results of the Work of. the Division of Entomology. Div. Bul. No. 22, n.s., pp. 54-55. Few harlequin cabbage bugs in the southern states this year. Close, C. P., & White, T. II. 1909. (labbage Experiments and Cul- ture. Md. Bul. No. 133, p. 195. Host plants and habits dis- cussed. Remedies. Trap crops of kale or mustard. Clean cul- tivation. ' " , Cockerell, T. D. A. 1900. Observations on Insects. N. M. Sta. Bul. No. 35, p. 23. Brief popular notes. . Conradi, A. F. 1907. Insects of the Garden. Tex. Bul. No. 89, p. 9. Distribution. Brief account of. life history and habits. Clean cultivation, trap crops, and burning suggested. Essig, O. E. 1915. Injurious and Beneficial Insects of California, p. 20. Description, life history‘, nature of work, distribution, food plants, control measures, and natural enemies. Felt, E. P. 1910. Garden and Grain Insects. N. Y. Bul. No. 490, p. 53. Specimens sent in from Elmira and Oswega-Jamaica, L. I., in 1900; from Orient Point, L. II, in 1910. Fowler, C. 1901. Some Insects of the Year. Calif. Bpt., 1899-1901, p. '77. Brief account of injury in three counties. C Fulton, H. R., Wright, W. J., Gregg, I. W. 1911. The Control 62 - TEXAS AGRICULTURAL EXPERIMENT ScrATroN. Insectssand Diseases Affecting Horticultural Crops. Pa. B N0. 110, p. 21. f Garman, H. 1895. The Harlequin Cabbage Bug. Ky. Rpt., 1895, 44 (fig. 6). Present in 1890. Life history notes, suggestio A as to remedy. 1904. Insects Injurious to Caggage. Ky. Bul. No. 114, 1904, pi 40. Plants and life history briefly discussed. Garcia, Fabian. 1890. Injurious Insects. N. M. Bul. No. 68, p. 10.’ Brief description, life history and habits discussed. Use trap ~ crops of mustard and radishes. Glover, Townsend. 1867. Report Commissioner of Agriculture, 1867, . . 71. ' 1870. Report Commissioner of Agriculture, 1870, p. 90. 1871. Report Commissioner of Agriculture, 1871, p. 18. 1875. Report Commissioner of Agriculture, 1875, p. 16, f. 3, p. 137. . Hahn. 1834. ~Wanzenartigen Insecten, II, 183, p. 116, f. 196. Ori- ginal description and distribution. Herrick, G. W. 1903. Report of the Botanist and Entomologist. Miss. Expt. Rpt., 1903, p. 24. Remedy suggested. Howard, L. O. 1897. Some Miscellaneous Results of the Work of the Division of Entomology. U. S. D. A. Bul. 7, Bur. of Ent., p. 80, also Bur. Ent. Cir. _No. 10. General notes. Johnwn, W. G. 1905. Proceedings of the Ninth Annual Meeting of the Association of Economic Entomologists. Notes from Mary- land. Kellogg, U. L. 1908. American Insects. Pp. 214-215. General account, distribution and hosts. Lincecum. 1-866. Practical Entomology, I, 1866, p. 110. History, habits. . Lintner, J. A.. 1875. Count. Gent., XI, 1875, p. 392-. Remedies. 1876. Count. Gent, XII, 1876, p. 565. ' 1878. Count. Gent, XIII, 1878, p. 616. 1880. Count. Gent., XIV, 1880, p. 679. Description, remedies, etc. ~ 1882. Mdzrgantia h/istrioziica (Hahn), N. Y., First An. Rpt. N ox Insects, 1882, p. 264. Description, natural history, distribution, and remedies. ' ' 1893. Zlluirgantia lzzlsfrinnim (Hahn), N. Y., Ninth An. Rpt. of Nox Insects, 1893, p. 315. 1895. N. Y. 11th Rpt. (An) of NoX Insects, p. 901, p. 280. Extending north from Maryand. Remedies suggested. Morgan, H. A. 1897. Entomological Report. La. Bul. No. 48, pp. '139-141. Description of two egg parasites are mentioned. Treatment. . Morrill. 1910. Plants-Bugs Injurious to Cotton Bolls. Bur. "Ent. Bul. 86, 38, 110. Frequents cotton.‘ STUDIES ON THE HARLEQUIN BUG. 63 Newell, W., & Rosenfield, A. 1909. Some Common Insects Injurious to Truck Crops. La. Crop Pest Cir. 27, p-. 97. Brief account and remedies. ~ . O’Kane, Walter. 1912. Injurious Insects, p. 191. Description, dam- age, habits, and control measures. , Packard, A. S. 1877. Haydens 9th Annual Report, U. S. G.-G. Surv. Terr., 1877, pp. 755, 757, f. 27.» IIabits, description, distribu- tion, etc. 1877. Insects of the West, p. 755. A review of previous publi- _ cations. .- Paddock, F. B. 1915. The Harlequin Cabbage Bug. TeX. Bul. 179, 1915. Popular account with control measures given. Parrott, P. J. 1894. Insects Affecting Late Cabbage. Geneva Bul. 83, p. 683. Found on radishes near Jamaica, N. Y. 1907. Studies on Garden Insects. Geneva Rpt., 1907, p. 246. Refers to Bul. 83. _ Pittuck, B. C., & McHenry, S. A. 1903. Cabbage. TeX. Bul. No. 69, 1903. Harlequin cabbage bug controlled by blow torch. Quaintance, A. L. 1899. Insect Notes for 1899. Ga. Sta. Rpt., 1899, pp. 141-145. Sprays, etc. Riley, C. V. 1869. The Harlequin Cabbage Bug. American Ent, Vol. 11, p. 79. 1872. The Harlequin Cabbage Bug. Fourth Rpt. Mo. Insects, 1876, p. 35. Injury to cruciform plants. Description and life history. ‘1876. The Harlequin Cabbage Bug. Coleman’s Rural World, Oct. 4, 1876. Habits, distribution, remedies and color of early stage. 1883. Insects in Relation to Agriculture.- Stoddart’s Enc. Am., _ p. 140. 1884. The Harlequin Cabbage Bug. Rural New Yorker, Feb. 2, 1884. Notes. 1884. The Harlequin Cabbage Bug. Rpt. of Gov. Ent, 1884. . Habits, remedies. . 1893. Injurious Insects of Maryland. Md. Bul. 23, 1893, p. 85. Popular notes and treatment. 1901. Insects A1°Fecting_ Cabbage and Cauliflower. Bur. Ent. Bul. 31, n.s., 1901, p. 87. Spreading north again. Sanborn. 1914. Garden and Truck-crop Pests. Okla. Bul. 100, p. 24. Description, life history, habits and remedies discussed. Sanderson, E. D. 1900. Report of the Entomologist. Del. Rpt., 1899-1900, pp. 210-911. Biological and economic notes, life history. 1902. The Harlequin Cabbage Bug. Del. Rpt., 1902, p. 139. Notes 3 to 5 broods. 1907. Insects of the Garden. Tex. Bul. 89, pp. 9-11.. Treat- ment, including plumber’s torch method. 1908. The Influence of Minimum Temperatures in Limiting the Northern Distribution of Insects. Jr. Eco. Ent., I, 4, p. 245. The harlequin cabbage bug is restricted by low temperatures. 64 TEXAS AGRICULTURAL EXPERIMENT STATION. 1908. Insects Injurious to Staple Crops, p. 27. Distribution, trap crops and spraying suggested. 1912. Insect Pests of Farm, Garden, and Orchard, p. 268. ‘Dis- tribution in the United States. Description, life habits, and control measures. Sherman, F, Jr. The Hzirlequin Cabbage Bug. N. C. State Dept. of Ag, Cir. 8. Life, history, habits, relief measures. Sherman, F, Jr. 1903. Iniurious Insects. N. C. State Bul. 24, p. 5. Short description, biological and economic notes. Sirrine, F. A. _]894. Insects Affecting Late Cabbages. N. Y. Sta. Bul. 83, n.s., Dec. 1894‘, p. 683, also N. Y. State Bpt, 1894. Brief notes. Smith, J. B. 1896. The Harlequin Cabbage Bug. N. J. Rpt, 1896, pp. 458-461. Notes on its nature, habits, life history. Sugges- tions as to remedies. 1897. The Harlequin Cabbage Bug and the Melon Plant Louse. N. J. Bul. 121, 1897. E. S. B, Vol. 9, p. 68. Preventive and ' remedial measures. . 1917. Control of Some Garden Insects. Va. Truck Expt. Sta. Bul. 23, p. 497. Notes on life history. Control methods, in- eluding a new spray. Smith, R. I. 1908. Some Insect Enemies of Garden Crops. N. C. Bul. 197, p. 18. 1908. Life history, habits, detail of life cycle, remedial measures discussed. - 1909. Biological Notes on Zl/[urgantitt histrionica (Hahn). Jr. Eco. Ent., Apr., 1909, p. 108. .' Egg laying habits, incubation of eggs, recorded egg laying habits of hibernating generation of second seasonal generation, life cycle, remedies. ' 1909. The Harlequin Cabbage Bug. N. C. Rpt, 1909, pp. 90-99. Life history studies; remedial measures suggested. Stal. Enumeratio H empt, II, p. 37, No. 4. Distribution. Stedm-an, J. M. 1893. Injurious and Beneficial Insects. Ala. Bul. 45, p. 28, 1893. Popular account and remedies given. Stelle, J. P. 1870. Southern Notes. Am. Ent., Vol. II, p. 155, March, 1870. Ravages. _ Stinson, J. T. 1895. Insects Injurious to Fruits and Vegetables and Remedies for Destroying Them. Ark. Sta. Rpt, 1895, p. 83, also Ark. Bul. 895. . Symons, T. B. 1905. The Common Injurious and Beneficial Insects of Maryland. Md. Bul. 101, p. 187, 1905. Description, life history, habits, and remedies. ’ Thomas, C. 1877. Sixth Bpt. Ins. Ill., 1877, p. 59. Brief general notice. Townsend, B. R. 18870. Harlequin Cabbage Bug. Am. Ent. and Bot., Apr., 1870. In letter tells of great number around Austin, Texas. Uhler, P. B. 1876. Bul. U. S. G. G, Surv. Terra, I, 1876, p. 290 p. 24 of sep. pag.)‘, 1, pl. 19, f. 9, Ib., III, 1877, p. 404. Sronrns ON THE HARLEQUIN BUG. i 65 U. S. Y. B. 1905. P. 629. Insects Injurious to Truck and Vege- table Crops. Injurious in gulf region and California; rare in most northern localities. 1906. Insects Injurious to Truck and Vegetable Crops. P. 511. After an absence of six years in latitude of District of Colum- bia reappears in noticeable number. _ 1907. Insects Injurious to Truck and Vegetable Crops. Again spreading northward. 1908. Insects Injurious t0 Truck Crops. Injurious in Virginia, Missouri, Alabama and California. Walsh. 1866. Prac. Entomology, I, 1866, p. 110. History, habits, etc. Watts, R. L. 1892. Fruit Trees and Experiments with Vegetables. Tenn. Bul., Vol. V, No. 1, p. 16. Cauliflower entirely do» stroyed, kerosene emulsion etFective. Hand picking used. Webster, F. M. 1896. Notes on the Distribution ofSome Injurious Insects. Jr. Ent. Soc, Wash, III, 288-290. Dispersion of species. 1896. Some Destructive Insects. Ohio Bul. 68, 1896, p. 35. Host plants, where found. Life history in north and south. Remedies. . 1899. Insects of the Year in Ohio. Bur. Ent. Bul. 20, n.s., p. '71. Low temperatures were a severe repulse to northward spread of this insect. 1901. Insects of the Year in Ohio. Bur. Ent. Bul. 31, n.s., p. 8'7. Harlequin cabbage bug reoccurred in Ohio. ' Weed, H. E. 1892. Insects Injurious to the Cabbage. Miss. Bul. 21, p. 12. Life history, habits, and. remedies. . Wilcox. E. M. 1901. Notes on Troublesome Insects and Plant Dis- eases. Okla. Rpt, 1901, p. 113. Five broods; last deposit eggs fromwhich are hatched the brood that winters over as partially mature adults. Worsham, E. L. 1909. Insects of the Year in GeorgiaQ Jr. Eco. Ent., Vol. 2, p. 209. Notes on frequency of occurrence in Georgia.