18 



of the order. This he endeavored to do for the groups in which 

 material was availahle for study, and he has since pubHshed other 

 articles as additional material was obtained. However, Dr. Chapman 

 attempted no classification of the Lepidoptera on this basis, merely 

 pointing out the pupal characters of the major groups and calling 

 attention to instances in which a study of these characters would ap- 

 parently alter the existing schemes of classification. 



The attention of American entomologists w^as called to this subject 

 by Dr. A. S. Packard ('95) in a paper entitled "Attempt at a New 

 Classification of the Lepidoptera." He made a new grouping of the 

 order based upon pupal characters and figured a large number of 

 species. His determinations of the homology of the various parts 

 of the pupae studied were far from correct, and this, of course, in- 

 validated many of his conclusions. 



Since that time nothing has been done in America towards a classi- 

 fication of the Lepidoptera based on pupal characters. The purpose 

 of the present investigation is to present such a classification as far 

 as material has been available for study. There is also an attempt 

 to throw some light on the relationships existing between the different 

 groups. 



Changes Preceding Pupation 



The person who begins the study of pupae with the preconceived 

 notion that the pupal stage is an interpolated one in the insect's life 

 and that a pupa bears little or no resemblance to either larva or adult, 

 will probably find abundant cause for a change of mind before his 

 study is completed. In the case of Lepidoptera one is apt to think 

 that no similarities could possibly exist between any of the three 

 stages of the insect's development after it leaves the egg. After care- 

 ful study, however, one is surprised with the resemblance between 

 the stages, for it is of the highest importance in the study of any 

 group to be able to homologize larval, pupal, and imaginal characters. 

 This has been done to some extent in certain orders of insects, par- 

 ticularly in those groups w^here the resemblance between the larva and 

 adult is more striking than in the case of the Lepidoptera. Attempts 

 have been made, however, even in this order, to homologize the 

 mouth-parts of the larva and adult, and some of the larval structures 

 have been homologized with certain structures in the pupa ; but appar- 

 ently the idea that all three stages should be studied has been left for 

 other minds to entertain. 



The first striking difference between larva and pupa is that of 

 size. This difference is easily explained by the great difference in the 

 size of the alimentary canal. Another striking difference is that the 



