182 PTILOTA. 



absence of ocelli, as well as a somewhat less perfectly deve- 

 loped organization of the antennae, and some other parts of 

 their structure, may, however, serve to distinguish them. 

 From analogy with the higher animals we might perhaps be 

 induced to consider, that these insects, which maintain a 

 constant activity throughout their existence, are much higher 

 in the scale of natiu-e than those species which, like the but- 

 terfly, are subject to so long a period of death-like repose. 



In the Heteromorphous di\^sion the larva is totally unlike 

 the perfect insect, being generally more or less vermiform, 

 and, with the exception of the head, of a leathery-like tex- 

 tm'e. Here belong the tribes of beetles, butterflies, moths, 

 bees, and most other four and two-winged flies, as well as the 

 flea. There are, however, various modifications of form in 

 respect to the head and legs of the larvae of those insects, so 

 that it may, perhaps, be advisable to give a sketch of their 

 distribution, proceeding from the more fully to the less per- 

 fectly developed species. 



A. Larva capitata, or those having a distinct head, sub- 

 divisible into 

 1. Hyperhexapod(B, or those having six legs, and a vari- 

 able number of membranous prolegs. The larvfe 

 of butterflies (fig. 14, larva of Camberwell beauty 



butterfly), raoths and saw-flies (fig. 13, larva of 

 Cimbex lutea). 



