82 



FRriT INSECTS 



¥u: 



So. — spring canker-worm, side 

 view (X 1^)- 



spiracles, and a wide greenish-yellow stripe bordered by black 

 lines along the middle of the venter (Fig. 85) . Usually 3 narrow, 

 more or less broken, yellow stripes can be distinguished ex- 

 ,4 tending along each side of 



the body above the spir- 

 acles. 



By June 1, most of the 

 caterpillars get their growth, 

 spin down from the trees, 

 and enter the ground an 

 inch or more, where they 

 transform in a simple earthen cell to the greenish-brown pupae 

 (Fig. 86). There is but a single generation annually, the 

 insect spending at least 9 months, including the winter, in 

 the pupa stage. 



Natural enemies of canker-worms. 



Some of the caterpillars often fall a prey to several hymenop- 

 terous and dipterous (Ta- 

 china) parasites, predatory 

 sucking bugs and ground- 

 beetles. Potter-wasps some- 

 times store their clay nests 

 with them, and other enemies 

 are mentioned in the discus- 

 sion of the fa;ll canker-worm. 

 But by fax' the most effective 

 enemies of canker-worms are 

 the birds. Over forty kinds 

 of birds, especially the chick- 

 adees, thrushes and warblers, 

 have been found feeding on 

 the caterpillars, the eggs or 

 the egg-laden female moths. Yet in spite of the efficient aid thus 

 rendered by the birds and other animal parasites, the cessation 



Fig. 



86. — PuptB of the spring canker- 

 worm. Enlarged. 



