Page:Insects - Their Ways and Means of Living.djvu/338

 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

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