52 MEMOIRS OF THE NATIONAL ACADExMY OF SCIENCES. 



is not well founded, since it is more jirobable that both Tiicboptei-a and Lepidoptera have had a 

 conimou parentage. On the other hand, all agree in placing the butterflies at the head of the 

 series as the most specialized modern group of families. But as regards the natural sequence of 

 the groups between these two assemblages there are wide differences of opinion. Certainly the 

 division of the order into Ithopalocera and Heterocera is amateurish and artificial, as is the 

 separation of the order into the divisions of Macrolei)idoptera and Microlepidoptera. 



The princii)les 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 of organic beings, an expression of the phylogeuetic development of the 

 members of the group. 



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

 diagnostic of adult Lepidoptera, as also the absence of functional mandibles, these characters, 

 together with the pupal ones, are of great phylogenetic importance and of primary taxonomic 

 value in the establishment of suborders. 



3. As in the case of the Diptera, which were divided by Brauer into Diptera cydorhapha and 

 ortUorhapUa, 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 Chapman, are, it seems to us, of fuudameutal importance in the classification 

 of the order into subdivisions of suborders, i. e., of superfamilies and families. Owing to the 

 adaptive characters of the imago and also of the larva we have hitherto been very nuich iu the 

 dark as to the most fuudameutal features, such as will be of permanent value iu the establishment 

 of the minor groups named. Yet it will be seeu that in general the imaginal characters agree 

 with the pu])al 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 pupae of Heterocera, a truly epoch-making one, we 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 pup:e 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 in 

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

 Mecoptera, Siphouaptera, Neuroptera, and Hymeuoptera. As regards the Colcoptera, it is 

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

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

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

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

 the writer attemjited to show that the campodea-form larva of the Meloids and Stylopidie weie the 

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

 that the scavenger and phytophagous fiimilies were derived from them; the weevils aud Scolytidse, 

 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 Noctuidiie, as well as the butterflies, this being probably 

 in part due to geological extinction. 



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

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



' Zur Morphologie der Schmetterlingsmundthcile, Sitzungsb. Jena. Ges. Med. und Naturwissens., 1885. Beitriige 

 iiir Morphologiu der ScUmetterlinge, Jena. Zeit., 1885, pp. 751-807. 



2 On some neglected points iu the structure of the pup.-e of Heteroeerous Lopidoptera and tlieir probable value 

 in classification, etc. Trans. Eut. Soc. Londou, 1893, pp. 97-119. 



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

 M. C. Houlbert, who has published a new classificatiou of the Coleoptera. See Eapports naturel et phylogduie 

 des Coleopteres. Bulletin des Sciences nat. de I'Association des Eleves de la Faculte des Sciences de Taris, iv. 

 May, 1894, pp. 62-171. 



