THE UNIVERSITY OF ILLINOIS LIBRARY F8V * THE CLASSIFICATION OF LEPIDOPTEROUS LARVAE BY STANLEY BLACK FRACKER A. B. Buena Vista College, 1910 M. S. Iowa State College, 1912 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN ENTOMOLOGY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1914 t FS4- UNIVERSITY OF ILLINOIS THE GRADUATE SCHOOL May 16 th 1904 1 HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Stanley Black Fr acker, A. E., M. S. ENTITLED The Classification of Lepidopterous Larvae BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy In Charg^of Major Work (J Head of Department Recommendation concurred in: Committee Q ) Final Examira ( (f^&^A^&yviS 884567 UlUC CONTENTS Acknowledgments - 3 • • PAPT ON F . THE HOMOLOGY Ui THE SET^i,. - . i r*r1'nf»thiOyi — 5 XT • Xi.1T>n't"Tv X UUU UXwli. — .lib tUI llul 6 Th p nhppto taxv of a t w i c a 1 s e rn e n t - 10 11 1 9 u Ltl C \J X C V iuuuuw ™ 1 "Hp -P-? ni "hi ona — - 11 - cP > Tiij_/XJ__iL/UXv>i.c<o-f-f'T pill "hi P^s - - 13 3a Cormarative InatOTHV - ~ 14 4. Onto^env - - — 16 — •J^ -• Vr>V C- riX X pCv tiu 1 UI1on — — 20 — . Y>"n1 i o"P A. 21 XT TX -XT • XJLA J vUnn tiOX Ullnn WX "hhpwllv \JevifieriC6V J. X\s \s 1 . Amplication of 'nr incinles 21 P. ('Vim' r»a nf n no^encl ature - 23 TV. Sftiifll ATTflrifpipnt in the ^TinciDc1 1 surjerfanilies - - - 26 Ttl CTO f-f) p _ _ — 27 Ofc • £1J,Q Q IHO UUJ. 27 Vl . Tifl "t"P 7* 1 nq +-,q yo _ _ 29 <"1 o*p p. (^nriplj iipi , "Pvrtm P ^ f".l 1 0"f Til tfi.fi jUilvlU01wUunn 1. 1 W . 1 C*< u UUU.^v \J — J 1*>>C- uc«v 35 ?« TTypvip 4-p p _ _ _ 36 V» ^rinarv and siAhnrinarv setre - - 39 Alpha, 40; leta, 41; Garama , 41; Delta, 42; Epsilon, 4E; P.ho , 43; Theta, 44; Zappa, 45; Eta, 45; Pi, 46; Mu, 49; Si^ma, 50; Tan, 50. VI. General conclusions 50 . , ^ Digitized by the Internet Archive in 2013 http://archive.org/details/classificationofOOfrac_0 PAET TWO. SYSTEMATIC OUTLINE OF FAMILIES AMD GEiUSRA. I. Introduction - II. Characters used - Head parts, 57; Armature of the body, Spiracles, 61; Prolers, 61; other structures, 64. III. Classification - Analytical table of families Suborder Jugatae Super family Mieropterygoidea Suborder Frenatae I.icrolepidoptera Tineoid series Superfamily Pyralidoidea Superfamily Zygaenoi&ae Ilacroheterocera Superfamily Bombycoidea Superfamily Saturnioidea Superfamily Sphingoid ea Rhopalocera - IV. Glossary - V. Explanation of plates VI. Bibliography VII. Plates - . ACMOWIJfiDGMBJJTS The subject of this paper was suggested by Professor Alexander D. MacGillivray in the fall of 1912«*. During the two yearf since that time the writer has "become more and more con- vinced of tiie necessity for and value of taxonomic studies of immature insects. Vhile a classification based on larvae would doubtless include as serious mistakes as one in which only the adults were considered, combining the t.vo methods results in the elimination of a great many errors. In addition to this purely scientific ideal, the demand of students and economic entomolo- gists for some means of identifying larvae without rearing them has acted as an even stronger incentive to persistent effort. The author wishes to express his sincere appreciation of the suggestions and criticisms of Professor MacGillivray through- out the preparation of the paper and of the inspiration which has come from association with him. The authorities of the Univer- sity of Illinois have, through liberal appropriation, made pos- sible the purchase of material from Dr. 0. Staudinger & A. Bang- Haas of Dresden, from the Xny-Scheerer Company, from the 7/ard Natural Science Establishment, and from Mr. 7ra. Beutenmuller They have alto enabled the writer to study for several months at T the United States national I useum % where the series of lepidopter ous larvae is probably the most extensive in the world. For se- curing this assistance, for continuous encouragement, and for placing at our disposal the material of the Illinois State Labor- atory of Natural History, Professor Stephen A. Forbes deserves our hearty thanks. Grateful acknowledgments are due Dr. L. 0. Howard for his courtesy in granting use of the entomological 4 collections of the National Museum. To Dr. Harrison 5* Dyar, Mr. Aurust Busck, and Mr. Carl leinrich, the writer^ is indebted for numerous suggestions and for making these collections acces sible and useful. 5 PARI uliK . THjj HOMOLOGY THE SETAE . r T I. Ix.x ..ODUCTIOiv . One of the moat serious difficulties la the path of scientific progress is the lcck of i mean, of expression com- non to all the .vorkers in a single field. ..hen a particular term means one thing to one scientist and something el. e to another no amount of learning will make the opinions of these mma intellirible to each other until they under; tand the dif- ference. In human anatomy, the large number of vorkers, the excellent figures, and the antiquity and narrow limits of the subject have to a large extent remove c this confusion hut in other fields of "biology the mistakes it causes are still ap- parent. This is true in entomology and very noticeahly so in the study of larvae. The various systems of numerals which have been ap- plied to the setal arrangement of lepidopterous larvae are all baset on the simple plan of numbering the setae from the dorsomeson. Except in the most conspicuous eases, little lonsideration is taken of the relations of t .e different seg- ments to each other. Several authors have already introduced confusion by allying the numbers in a slightly different way from that first sur;estec but no careful investigation has been made of the real relations of the larval chaetotaxy of one group to that of another. Realizing the conflicts in the application of the 6 minerals now in use and the nature of the objections to thern, the writer began the study of caterpillar! with an investi- gation of the homology ancl honotypy of the setae. The ob- ject of the former was a determination of the changes which have taken pla.ce in the ancestral history of any particular body eegme it, such as the prothorax, and the application of a given name to the same structure throughout the entire or- der. The study of the latter, homotypy , .vas taken ur> for the purpose of finding the relation of the setal pattern of the different body segments to each other, in the hope of airily in? the same name to the same structure throughout the entire body. All the se-ments behind, but not including, the head were studied and satisfactory results were obtained for all ereerit the tentn or last abdo^i ml segment. It if intended that the figures, dec cri^t ions , and definitions shall make every statement in this par>er abso- lutely definite ancl that they shall be ;_o clear that a novice may be able to make a complete description of a catemillar without the possibility of confusion as to his meaning. New species and new ins tars should be described in a manner which will make like specimens recognisable in the future without repeating the breeding. 2uch co-g^letc descriptions in t::e published records are very few at the present time. His torical . The number of na^ers bearing on this -oroblem is by no means sraall and yet the contributions to its solution have been surprisingly slight. The first worker to find and des- f 3 c - 7 cribe a primary plan of the setae of caterpillars was Vilheln Miller, '86, in a paper on the i^ym^halidae . After diseussin the arrangement in the first sta.^e of these butterfly larvae, he says, "We find in the first stae, on the abdomen of all forms considered, certain set- e. Tho of many different form their constant arrangement sho vs then to he homologous. ,7e call these setae primary. " Doubt aj to the similarity between the mesothorax and raetathorax and the abdomen seems to be out of the question." In an appendix, brief notes on the chaetotaxy of the larvae of other families of Le^idoptera are given. Careful comparison is made between the Batumi oidea and tl e Sphingidae. Dr. Harrison 3. Dyar did not fine this paper and in 1894 again discussed the subject as new and numbered the pri- mary setae. So far as I kno.v, this author makes the first suggestion that the position of the setae be used in classi- fication. Sis observations included a few representatives of many families and his phylogen:; as based on them is remark- ably good. lie also numbers the metathoracio setae but makes no attempt to shov that the seta bearing a certain number on • te abdomen is homologous to one bearing the same number on the thorax. He, himself, realized that the met,; thoraci TT tubercles'' ia-|-ib and iia-j-iib , were not the homotynes of the abdominal setae, i and ii, anc in 1931 made a definite state- ment to that effect. This discussion, therefore cannot be f considered a contribution to the study of horaotypy* In another paper the following year the same author 6 reported observa tiom on the first stares of many larvae, finding that they differed considerably fro-, following staget- By these observations he established the primary arrange merit o:' the setae on the abdomen and demonstrated its uniformity throughout a preat part of the order.