INSECTS AFFECTING GRAINS, GRASSES, ETC. 91 



nificant, when assembled in countless myriads chinch-bugs have 

 doubtless been of greater injury to the farmers of the Mississippi 

 Valley than almost any other insect attacking grain crops, the total 

 damage from 1850 to 1909 being estimated at $350,000,000.* 



Life History. During the winter the bugs hibernate in clumps 

 of grass, in corn butts, and in old shocks of corn, or under what- 

 ever rubbish is available. In early spring they assemble in 

 fields of grass and small grains. Soon they pair and the females 

 commence to lay their small yellowish-white eggs upon the 

 roots or bases of the stalks, each laying some 150 to 200 eggs. 



FIG. 70. The chinch-bug (Blissus leucopterus Say): adult at left; a, b, eggs 

 magnified and natural size; c, young nymph; e, second stage of nymph; 

 /, third stage; g, full-grown nymph or pupa; d, h, j, legs; i, beak through 

 which the bug sucks its food. (After Riley.) 



The eggs are laid from the middle of April until the first of 

 June, depending upon the latitude and weather, and hatch in 

 two or three weeks. As the nymphs grow they often do serious 

 injury to small grains and grass, upon which they become full 

 grown about the time of harvest. When wheat is harvested 

 they spread to oats and soon to corn, but, curiously enough, though 

 the adults have wings they travel from field to field on foot, were it 

 not for which fact we should be at a loss to cope with their migra- 

 tion. Eggs are now laid upon the unfolding leaves of the corn, 

 from which the nymphs commence to emerge in about ten days. 

 This second brood matures on corn in August and September and 

 is the one which later hibernates over winter, though where corn 

 is not available the whole season may be passed on grass. 



* See Circular 113, Bureau Entomology, U. S. Dept. Agr., F. M. Webster* 

 and Headlee and McColloch, Kansas Expt. Sta. Bulletin No. 191. 



