Article; II. — A Classification of the Lcpidoptera based on Char- 

 acters of the Pupa* By Edna Mosher, Ph.D. 



Introduction 



» It is within comparatively recent times that the immature stages of 

 insects have been considered of any taxonomic value. The economic 

 entomologist early realized the value of being able to recognize the 

 immature stages, for in many orders of insects the larval stages alone 

 were responsible for many ravages upon crops and orchards. Still the 

 matter was not taken up by the systematists, and the workers in the 

 field of economic entomology contented themselves by rearing the adult 

 to determine the species, and then describing, perhaps all the stages, or 

 more probably the larval and adult stages as being those of economic 

 importance. Nowadays we are beginning to see that it is impossible 

 to construct an adequate classification of any group of insects unless 

 we use every bit of information obtainable on their life history and 

 habits. 



It is possible to multiply instances of the value of the larval stages 

 in classification, so that one scarcely needs to cite examples ; but the 

 pupae have been less frequently used. There are cases, however, in 

 which the only good taxonomic characters available are found in the 

 pupal stage of the insect. Such instances are found among the nema- 

 tocerous Diptera, particularly in the family Chironomidae. Scudder 

 ('89) was the first to attempt a classification of lepidopterous pupae, 

 but his keys to the chrysalids were based, not on structural characters, 

 but on the various projections from the body, the cuticular append- 

 ages, the coloration, and the mode of suspension. 



Among the Lepidoptera a great deal of work has been done towards 

 the classification of the larvae, but until 1893 nothing of importance 

 had been done towards a study of the pupae. In this year Dr. T. A. 

 Chapman, in a paper entitled "Some Neglected Points in the Pupae 

 of Heterocerous Lepidoptera," called attention to the fact that the 

 pupae possessed some remarkable taxonomic characters which might 

 be used to clear up many of the disputed points in the classification 



•Contribution from the Entomological Laboratories of the University of Illi- 

 nois, No. 48. 



