xin. 



SOCIAL CATERPILLARS 



As a general rule, caterpillars of butterflies live 

 solitary lives throughout their entire existence. 

 The mother drops an egg here and there upon a 

 spot suitable for the food of its young, and here the 

 caterpillar takes up its abode with more or fewer 

 wanderings. In two of the four families of butter- 

 flies there is scarcely a single exception known to 

 this rule, but in the highest family and in a few 

 instances in the Papilionidae, caterpillars during 

 at least a portion of their lives are more or less 

 gregarious. Whenever the caterpillars are strictly 

 gregarious, the eggs are invariably laid in clusters ; 

 there are, however, some butterflies which lay their 

 eggs in small clusters, whose caterpillars are not 

 properly gregarious ; yet all such are closely re- 

 lated to others whose caterpillars are gregarious, so 

 that we find every gradation from solitary to social. 

 There are also some caterpillars which are gre- 

 garious in their early life, but afterward part com- 



