52 IMEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



is not well foiinded, since it is more probable that both Trichoptera and Lepidoptera have had a 

 cotniuon parentage. On the other hand, all agree in plaeing the butterllies at the liead of the 

 series as the most specialized modern gron]) of families. But as regards the natural se(]uenee of 

 the groups between these two assemblages there are wide ditl'erences of opinion. Certainly the 

 division of the order into ]fho])alocera and Ileterocera is amateurish and artificial, as is the 

 sepai'ation of the order into the divisions of ."Macrolepidoptera and .Microlejiidoptera. 



The principles which it seems to us should be kept in view in working out the relations of the 

 groups are the following: 



1. "We should keep constantly in mind that a true classification of the Lepidoptera is, like 

 that of any other group ot organic beings, an expression of the i)hylogenetic development of the 

 members of the group. 



2. The mouth-parts and particularly the highly modified and specialized maxilla>, being 

 diagnostic of adult Lcpidoiitera, as also the abseiu'c of functional mandibles, these characters, 

 together with the pupal ones, are of great phylogenetic importance and of i)rimary taxonomic 

 value in the establishment of suborders. 



3. As in the case of the Dijitera, which were divided bj- Brauer into Dipfera cyi-lorliaplin and 

 orthorhapha, the pupa serving for a division of the order into suborders, the larval and imaginal 

 characters agreeing with those drawn from the pupa, so "the pupal characters of Lepidoptera, as 

 first employed by Chapnmn, are, it seems to us, of fundanumtal importance in the classification 

 of the order into subdivisioTis of suborders, i. e., of superfaniilies and families. Owing to the 

 adaptive characters of the imago and also of the larva we have hitherto been very much in the 

 dark as to the most fundamental features, such as will be of permanent value in the establishment 

 of the minor groujjs named. Yet it will be seen that in general tlie inmgiual characters agree 

 with the pupal ones. 



Thanks to the labors of Walter' on the mouth-parts of the imago of Eriocephala, and to 

 Dr. T. A. Chapman's- paper on the pupa^ of Ileterocera, a truly epoch making one, mc now have 

 ■clews to the arrangement of the order which promise the most valuable results. Inspired by the 

 labors and suggestions of these two authors, I have endeavored, after studying the structure of 

 Eriocephala and Micropteryx and what pupa^ of other forms could be collected, to work along 

 the lines laid out in these papers. 



Those entomologists who disbelieve in the importance of the transformations of insects iu 

 taxonomy should bear in mind the value of larval as well as pupal characters in the Trichoptera, 

 Mecoptera, Siphonaptera, Neuroi)tera, and Ilymenoptera. As regards the Colcoptcra, it is 

 evident that their classilicatiou thus far as based on adult characters is quite unsatisfactory, the 

 more generalized forms having been placed at the head of the order and the extremely modified 

 weevils (Rliyncophora) regarded as the "lowest" group, and that we shall have to depend on the 

 larva; for the clew which will lead to a revision based on scientific evolutional principles. In 1883^ 

 the writer attempted to show that the campodea-form larva of the Meloida' and Stylopida; were the 

 most generalized coleopterous larva?, that the primitive Coleoptera were carnivorous forms, and 

 that the scavenger and phytophagous families were derived tVon) them; the weevils and Scolytida-, 

 instead of being the lowest, proving to be really the most modified and, therefore, recent groups. 



4. The older, more generalized groups of moths are much less numerous in number of species 

 than the more modern and .specialized groups; such are the generalized Tineina and the Bombyces 

 as compared with the Geometrida; and Noctuidixj, as well as the butterflies, this being probably 

 iu part due to geological extinction. 



5. While the i)eculiar shape of caterpillars, with their round heads, reduced cephalic append- 

 ages, three pairs of jointed thoracic feet, and abdominal legs, not exceeding live pairs, is diagnostic 



I Zur Morj)li<)loj;ic diT ScbmetterfiugsmiuHUbcilo, Sitzuiifjsh. Jcua. Gcs. Mi-d. uiul Naturwissens., 1885. Beitriige 

 zur Moriiliologic der Schniotterlinge, .Jena. Zeit., 1885, jip. 751-807. 



-On some neglected points in tlic structure of the pnpa^ of Heteroceroua Lopidoptera and their i>robable value 

 in classitiration, etc. Trans. Ent. Soc. London, 1893, pp. 97-119. 



^Third Heport U. S. Entomological Commission, 1883, p. 299. This view has been adopted and extended by 

 M. C. Houlbert, who has i)ublisbed a new classification of the Coleoptera. See Rapports naturel et phylogdnio 

 des Col<<opti-res. Bulletin dcs Scieucts uat. de I'Association des EIcvcs de la Facultd des Sciences de I'aris, iv, 

 May, 1894, pp. 02-171. 



