128 SOCIAL CATERPILLARS 



pany. In such cases the caterpiUar usually hiber- 

 nates, and its social life lasts to some degree 

 throughout the autumn and winter, the company 

 dis23ersing at the renewal of activity in the spring. 

 Indeed, in almost all cases, the association is most 

 conspicuous in early life, when the caterj)illars feed 

 in rows upon the same leaf in such close proximity 

 that it would seem to interfere with convenience. 

 Sometimes this is the only mark of their social na- 

 ture ; but as all caterpillars spin more or less silk 

 in moving about, a web of greater or less extent 

 generally accompanies a colony, and in some cases 

 the community constructs a close structure within 

 which they retire to rest or to moult. A Mexican 

 butterfly, allied to our sulphurs, constructs a web, 

 first noticed by Hardy, which is nearly as close as 

 parchment. With rare exceptions, all butterfly 

 caterpillars feed upon the outside of plants ; but 

 there are a few which live in the interior, and one 

 of these, an Indian S23ecies of Lycaenidae, is known 

 to be social, living in numbers within the fruit of 

 the pomegranate. 



Among our own butterflies, there is nearly every 

 gradation from brief and partial companionship 

 up to a social life which lasts throughout the entire 

 period of larval existence. The weakest form of 



