'INSECTS AFFECTING GRAINS, GRASSES, ETC. 83 



The adult moth (Fig. 60) is a fawn-gray or mouse color, with 

 the outer third of the fore-wings paler and bordered within by a 

 whitish cross-line. 



Life History. The eggs are laid in the fall on the stems of 

 weeds and grasses, in masses of fifty or sixty, near the ground. 

 They are about one-fiftieth inch in diameter, circular, grayish 

 in color, with radiating ridges. They hatch in late May in 



FIG. 60. The stalk-borer (Papaipema nitella Gn.): a, adult; 6, half -grown 

 larva; c. mature larva in burrow; d, side of one of its segments; e, 

 pupa all slightly enlarged. (From Chittenden, U. S. Dept. Agr.) 



southern Minnesota and the young caterpillars at once commence 

 to mine small galleries in the leaves of the food plants, soon 

 riddling the leaves. In a few days they work down to the bases 

 of the leaves and enter the stalks, which they tunnel out and not 

 infrequently leave one plant and migrate some little distance 

 before entering another. Infested plants are readily recognized 

 by the wilting of the parts above the larva, the work in corn 

 being particularly noticeable and having given the local name 

 of " heart-worm." The larvae become full grown about the 

 first of August. They are readily recognized by the peculiar 

 markings of the body (Fig. 60, b). The larva is about an inch 

 long and varies from purplish to whitish brown, and is marked 



