68 INTRODUCTION. 



unsightly the otherwise umbrageous trees of the fo- 

 rest, by consuming their leafy verdure. Almost their 

 only employment, indeed, is to eat ; and so indus- 

 trious are they at this agreeable occupation, that they 

 often consume, in the course of twenty-four hours, 

 double their own weight of food — a degree of vo- 

 racity of which we find no example among the higher 

 animals. Their structure is admirably adapted to 

 their mode of life ; and their singular habits and eco- 

 nomy render them even more interesting objects of 

 observation in this preparatory state, than after they 

 have assumed their more perfect and imposing form, 

 when, 



No longer reptile but endowed with plumes, 

 They through the blue air wander. 



The body of caterpillars is long and nearly cylin- 

 drical, and is divided, by deep incisions, into twelve 

 segments, exclusive of the head. The outer inte- 

 gument, or skin, is usually membranous and soft, but 

 in some instances it approaches more to a coriaceous 

 texture. The general softness of the body is of 

 great utility, as it thereby acquires great flexibility, 

 and readily accommodates itself to the various curves 

 and inflections which the insect is continually giving 

 to it, and which are rendered necessary from the man- 

 ner in which it obtains itP food. Most of the cater- 

 pillars that produce day-flying Lepidoptera, have 

 sixteen legs, which are of two distinct kinds. Six 

 of them are placed on the three anterior segments 

 — that portion of the body which corresponds to 



