LEriDOPTEROtfS INSECTS. 17 



pillars originating from eggs thus deposited are 

 solitary, as those originating from clustered eggs 

 are gregarious. The latter moreover remain in 

 company so long as they are in the caterpillar state, 

 while the former always occur dispersed, and lead a 

 solitary life. In this manner, then, the caterpillars 

 under notice live from the time they are hatched, 

 and even exhibit the same disposition when they 

 prepare for their change into the chrysalis state, as 

 we shall afterwards see. 



" As to their manner of growth, such caterpillars 

 differ widely from other animals which grow re- 

 gularly in all their parts as they are supplied with 

 nourishment ; but our caterpillars, on the contrary, 

 grow only in their inward parts, whose increase 

 puffs out the skin or outer covering that does not 

 grow, and hence becomes too small, so that at 

 length it must give way. In fact, it actually does 

 so, and this happens more than once during its life ; 

 a circumstance which I term the casting of the skin, 

 and which is thus performed : A few days before 

 the skin is cast, the caterpillar remains nearly sta- 

 tionary in the same place, and leaves off eating. 

 About this period, the neck or hind part of the 

 head may be observed to swell, in consequence of 

 which the old skin becomes more stretched, the 

 inner skin is separated from the outer, and in some 

 smooth caterpillars the head may be decerned shi- 

 ning through. The old skin becomes gradually 



