176 APPLIED ENTOMOLOGY 



of the body. In later stages the red becomes vermiHon, with a pale band 

 across the front of the abdomen, the head and prothorax dusky and 

 before becoming adult the red becomes quite dark. 



Development, at least for the individuals coming from the later eggs, 

 is not complete before harvesting time, and to finish their growth they 

 are obliged to migrate and find more food. They accordingly march in 

 armies, often travelling some little distance on foot, and many which 

 have already become adults, able to fly, march with them. In new feeding 

 grounds development is completed and the eggs for a second generation 

 are laid. This generation appears to feed more particularly on corn, 

 kafir corn, millet and other, similar crops, and its members become 

 adult before winter, and go into hiding until the following spring. 



With the short-winged form, hibernation at a distance from its food 

 plant is impossible because of its inability to fly. This form therefore 

 winters in grass-land and begins its work there in the spring. It is a 

 question whether there is more than one generation a year for this form. 

 Migrations when they occur, are of course on foot, and corn is no more 

 liable to be attacked than timothy or any other grass crop. 



The Chinch Bug is particularly affected by weather conditions, 

 dry weather being favorable, and wet seasons unfavorable. Dry weather 

 appears to induce migration, and a succession of several dry years 

 favors a large increase in their numbers and consequently of the injury 

 they cause. Rains during the hatching periods of the eggs are very 

 destructive to the insect, and the suppression of a Chinch Bug attack, 

 anticipated because of the great abundance of the wintering bugs, by 

 heavy rains at the right time in the spring is one reason why these pests 

 are not even more serious than is the case. 



A fungus {Sporotrichu7n glohuliferum Speg.) generally called the 

 "Chinch-bug Fungus" frequently attacks this insect, particularly during 

 periods of wet, cool, cloudy weather, and then kills enormous numbers 

 of them. In dry seasons it seems to have little effect, and attempts 

 to control the Chinch Bug by placing individuals inoculated with the 

 fungus in infested fields, while successful from the experimental stand- 

 point, have on the whole, hardly produced the results hoped for. It 

 is most valuable in seasons which are dry during the egg-hatching period 

 but wet thereafter. 



In seasons then, when rains occur during the egg-hatching periods 

 of the bugs, these and the fungus present will usually prevent serious 

 outbreaks. In dry seasons, and particularly where there are several in 

 succession, artificial methods of control must be resorted to. 



Control. — Numerous methods of control have been tested, with vary- 

 ing degrees of success. Destruction of the adult bugs while wintering, 

 has proved to be an efficient treatment when conditions are such as to 

 make it reasonably complete. Burning over fields where the bugs are 



