A Classification of Lepido2)terous Larvse. 201 



base is prolonged and chitinized, thus converting the tubercles into 

 large branching processes, each branch tipped with a hair. In the 

 Sphingidse it appears that all the tubercles have disappeared except 

 the dorsal one on the 8th segment, which forms the well-known 

 "caudal horn/' In some of the Saturnina, we have the set^e modi- 

 fied into urticating spines as in the case of the Eucleidas. This 

 similarity does not imply relationship as Dr. A. S. Packard seems 

 to believe,' since we have only a similarity in function, while the 

 structure of the bases of the tubercles is essentially different. 



On the Material Used. 



In the latest list of North American Lepidoptera- there are 

 enumerated sixty-three families, eliminating a few which have 

 since been united with others. I have found it impossible to 

 obtain the necessary material to make observations on all of these. 

 Especially in the group Tineina, which contains nineteen families, 

 my material has been very scant. I have not been able to avail 

 myself of the numerous descriptions of lepidopterous larvge scat- 

 tered in various journals, and only to a small extent of published 

 figures, since the former have been drawn up without any reference 

 to the arrangement of the tubercles, while the latter are (with a few 

 notable exceptions), either without accuracy or drawn in such posi- 

 tions that it is impossible to determine the arrangement of these 

 structures. I have not considered families which occur exclusively 

 outside of North America, on account of the total lack of material. 



I am indebted especially to Professor J. H. Comstock for many 

 alcoholic specimens, and to Dr. A. S. Packard for the loan of several 

 which I would not otherwise have seen. 



The Classification of the Lepidoptera. 



Before proceeding to a detailed description of the tubercles of the 

 various species which I have examined, a few general remarks are 

 in order. I have already indicated how well the present classifica- 

 tion drawn from the characters of the tubercles of the larva corre- 

 sponds with Prof. Comstock's classification from the venation of 

 the adult. The essential feature in which this classification differs 



1 See Journal N. Y. Entomol. Soc, vol. I, p. 9. 



2 List Lep. Boreal Amer., .T. B. Smith, 1891., 



