THE HEMIPTERA 



175 



up the Atlantic Coast, the Mississippi Valley and the Pacific Coast, and 

 is now found everywhere south of the St. Lawrence River and the Great 

 Lakes and also in southern Ontario, Minnesota, Manitoba, the Dakotas 

 and along the eastern slope of the Rocky Mountains to Texas. It has 

 also been found in Arizona, California and Washington. It is not a 

 serious pest usually in the northeastern states and many of the others, 

 but in the Mississippi Valley it often destroys crops valued at a hundred 

 million dollars, in one season. 



The adult bug (Fig. 166) is a tiny insect seemingly incapable of causing 

 so much injury, but its enormous numbers make up for its small size. 



a b c 



FIG. 166. Different stages of the Chinch Bug (Blissus leucopterus Say): a, nymph 

 in first instar; b, fourth instar nymph; c, adult. All enlarged about nine times. (Modified 

 from III. Agr. Exp. Sta. Butt. 95.) 



Its body is black or dark gray, with white and therefore conspicuous 

 wings, each having a single black spot. There are two forms of adult, 

 however, one with long, full-sized wings; the other with short wings 

 only partially covering the top of the abdomen. The former occurs in 

 the Mississippi Valley while the latter is met with, together with the long- 

 winged form, in the Atlantic States and to some extent inland from there 

 along the more southern of the Great Lakes to Illinois. 



The long-winged form passes the winter as the adult in grass tufts, 

 under fallen leaves or in other places giving it protection. Corn shocks 

 left out over winter often harbor enormous numbers. In spring the bugs 

 leave their winter quarters and fly to the grain fields. Here they lay 

 their eggs, several hundred in number, on the ground at the base of the 

 plants or on the roots just below the surface, this process lasting about a 

 month. The average length of the egg stage is about 2 weeks and the 

 young which hatch, suck the sap from the plants for about 40 days before 

 becoming adult. The nymphs are yellow with an orange tinge about 

 in the middle of the abdomen. This soon spreads over the greater part 



