INSECTS 



tion. Birds often poke holes in them with their bills and 

 rip off sheets of silk which they carry away for nest-build- 

 ing purposes. The caterpillars do not even repair these 

 damages. The rooms of the tent become filled with ac- 

 cumulations ot frass, molted skins, and the shriveled 

 bodies of dead caterpillars. The walls are discolored by 

 rains which beat into the openings and soak through the 

 refuse. Thus, what were shapely objects of glistening silk 

 are transmuted into formless masses of dirty rags. 



But the caterpillars, now in their finest dress, are ob- 

 livious of their sordid surroundings and sleep all day 

 amidst these disgusting and apparently insanitary condi- 

 tions. However, the life in the tents will soon be over; 

 so it appears the caterpillars simply think, "What's the 

 use?" But of course caterpillars do not think; they arrive 

 at results by instinct, in this case by the lack of an instinct, 

 tor they have no impulse to keep the tents clean or in 



repair when doing so 

 would be energy wasted. 

 Nature demands a prac- 

 tical reason for most 

 things. 



The tent lite continues 

 about a week after the 

 last molt, and then the 

 family begins to break 

 up, the members leaving 

 singly or in bands, but al- 

 ways as individuals with- 

 out further concern for 

 one another. Judging 

 from their previous me- 

 thodical habits, one would suppose that the caterpillars 

 starting off on their journeys would simply go down the 

 trunks of the trees and walk away. But no; once in their 

 life they must have a dramatic moment. A caterpillar 

 comes rushing out of a tent as if suddenly awakened from 



[28ol 



Fig. 150. A tent caterpillar in the last 

 stage of its growth, leaving the tree con- 

 taining its nest by jumping from the end 

 of a twig to the ground 



