288 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



markings of the body (Fig. 211, b). The larva is about an inch 

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

 with five white stripes, one along the middle of the back, and two 

 on each side. These sides stripes are absent on the first four 

 segments of the abdomen, giving the larva an appearance as if 

 it had been pinched or injured there. As the larva matures the 

 stripes become fainter. When ready to pupate the larva cuts a 



FIG. 211. The stalk-borer (Papaipema nitella Gn.): a, adult; b, 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.) 



hole through the side of the stalk, and then transforms to the 

 brown pupa in the lower part of the stalk. The pupal stage lasts 

 about two or three weeks, and the moths emerge in late August, 

 there being but one generation a year. 



Usually the injury to crops is only in the outer rows, to which 

 the larvae have migrated from weeds growing along the edges, 

 or in fields which have been weedy in early spring, or where the 

 weeds have been allowed to get a start before being culti- 

 vated out. 



