NS ECTS
tion. Birds often poke holes in them with their bills and rip off sheets of silk which they carry away for nest-build- ,ng purposes. The caterpillars do not even repair these damages. The rooms of the tent become filled with ac- cumulations of frass, molted skins, and the shriveled bodies of dead caterpillars. The walls are discolored by tains which beat into the openings and soak through the refi?se. Thus, what were shapely objects ofglistening 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 dav. anaidst 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 i'nstinct, for they h?ve no impulse to keep the tents elean or in
Fro. ??o. 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
repair when doing so would be energy wasted. Nature demands a prac- tical reason for most things. The tent lire continues about a week after the last molt, and then the family begins to break up, t[ae members leaving singly or in bands, but al- wavs as individuals with- Otl[ further COllcerll for one another. Judging from their previous me-
thodical habits, one ??ould 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
[ ?8o ]
THE
