INSECTS ON THE FARM 



303 



389. The chinch bug distribution. The chinch bug, one of 

 the greatest pests to grain and grass crops, is found generally 

 distributed over the United States east of the iO5th meridian. 

 The worst injury, however, occurs to the small grains and to 

 corn in the Central States, and it has been estimated that the 

 average annual loss to crops amounts to $40,000,000. 



390. Life history and habits of the chinch bug. This insect 

 passes the winter as an adult in clumps of grass, in corn shocks, 

 and under rubbish. The adults emerge from hibernation from 



FIG. 150. Stages in the development of the corn-ear worm 



A, egg ; B, caterpillar ; C, pupa ; Z>, adult. (All enlarged.) (After Headlee and 

 McColloch) 



March to May and move to the small grainfields. After feed- 

 ing for some time the females begin depositing eggs on the 

 roots or in the leaf sheaths of the plants (Fig. 151). 



These eggs hatch in from two to three weeks and the young 

 bugs feed in the small-grain fields until harvest, when they 

 migrate to the cornfields. Here they reach maturity and eggs 

 are laid on the corn plants or on the grasses in the cornfield. 

 These eggs hatch in about two weeks and the second brood feeds 

 and matures in the cornfields. Generally all the bugs have 

 reached maturity from the middle to the last of September. 

 When the food is gone or cold weather comes, the adults migrate 

 to their winter quarters. 



