138 BUTTERFLIES 



tent. This habit of working together for the common 

 good is very suggestive of the similar habits of the Ameri- 

 can tent caterpillars. Doors for going in and out are 

 left in the tent during its construction. 



The tent thus made is likely to be deserted after the first 

 moult and a new and larger one constructed on another 

 part of the plant. Two or perhaps three such nests may 

 be made from the time the caterpillar hatches until after 

 the second moult. The last nest made is very likely to be 

 upon some neighboring bushy plant or at least to include 

 some branches of such a plant if the bulk of the nest is 

 made upon snake-head. For after the third moult the 

 caterpillars stop feeding and become more or less quiet, 

 thus beginning a nine months' fast, during which they are 

 simply to wait until the return of spring. This fast may 

 be begun any time from the middle of August until early 

 in September, and even when brought indoors the cater- 

 pillars cannot be induced to eat. It is evidently the way 

 in which the species has bridged over the winter during the 

 thousands of generations of its existence, and the instinct 

 is so firmly fixed that it cannot be changed. Even in 

 West Virginia, where the caterpillars would have plenty 

 of time during the summer to mature as butterflies that 

 would bring forth another generation of caterpillars that 

 might pass the winter, the condition is the same as in the 

 far northern regions. 



So within the shelter of the silken nest these Baltimore 

 caterpillars remain from the middle of August until May. 

 Then when the spring sunshine has sufficiently warmed 

 their cool retreats they come forth and feed greedily upon 

 the young leaves. They now soon make up for lost 

 time and complete their growth as caterpillars very 



