INSECTS, HARMFUL AND OTHERWISE 221 



the tent, which is a good protection against many of their 

 enemies. At night it helps to protect them from the 

 cold, and it also sheds rain. As the caterpillars crawl 

 about on the tree they spin out a thread of silk over the 

 path they take. This may aid them in finding their way 

 back to the tent, and also enables them to let themselves 

 down from the branch or leaf to the ground. After reach- 

 ing maturity the caterpiller crawls or spins down from the 

 tree, and seeking shelter under sticks, stones, bark, etc., 

 goes into the cocoon or pupa state. From this emerges a 

 dusky, streaked moth. The nests should be removed with 

 the colony as soon as noticed, and should be burned. Birds 

 are useful in ridding us of this pest, especiahy the winter 

 resident woodpeckers, chicadees, nuthatches, etc., which eat 

 the eggs. The cuckoo and oriole destroy many of the cater- 

 pillars in summer. Most birds do not like the hairiness of 

 the common tent caterpillars and hence leave them alone. 



The forest trees are affected like the orchard and shade 

 trees. Large tracts of forest are sometimes defoliated by 

 tent caterpillars, canker-worms, tussock-moths, and other 

 leaf-eating caterpillars. Leaf mining or eating beetles also 

 do much harm to the foliage. The borers injure the bark and 

 wood of the stem and roots. Gall-forming insects attack 

 many forest trees and injure the leaves and twigs. In fact, it 

 is often impossible to find a perfectly sound leaf in the latter 

 part of the summer, so widespread is the injury done by 

 insects. 



The farmer has some very bad insect enemies to contend 

 with. Potato-beetles, chinch-bugs, army-worms, weevils, and 

 locusts sometimes cause the ruin of prosperous farmers, so 

 that such an insect plague becomes a national calamity. 



