ANCESTRY AND CLASSIFICATION. 251 



osmateria in function, general structure, and de- 

 gree of development, occur in single genera of 

 beetles, while totally absent from their nearest 

 allies ; yet nobody on that account claims for 

 them a high rank. In the larvae of certain moths, 

 such as Cerura, we find a much more extraor- 

 dinary special development than the caterpillars 

 of the swallow-tails can boast ; the anal prolegs 

 become long cylindrical tubes, extending back- 

 ward and upward, from out of which, when pro- 

 voked, the caterpillar thrusts a highly colored 

 and banded fleshy tentacle, with which it lashes 

 its body to frighten away intruders. Yet in 

 other points of its structure it perfectly agrees 

 with its kindred. Then again, if we examine the 

 lips of the closed osmateria of the swallow-tails, 

 we shall find them of a corneous nature, resem- 

 bling no other feature in butterfly larvae than the 

 chitinous dorsal shield on the first segment of the 

 caterpillars of skippers. We have therefore in 

 the very osmateria indications of a low origin, a 

 relationship with the skippers, which most other 

 points in the structure of the swallow-tails ex- 

 hibit. The recurved club of the antenna recalls 

 most strikingly the structure of the antennal tip 

 of the higher skippers, and is unlike that of any 

 other group of butterflies. The inner border of 

 the hind wing also is folded, just as it always is 

 in the skippers and rarely in other butterflies. 



