192 



COLEOPrERA— BEETLES 



etc., and feeds perhaps on the j>ollen of these flowers. In 

 some cases it is quite remote from the corn fields. They 

 deposit eggs in the ground. The eggs remain over winter 

 and hatch the following spring shortly after the corn begins 

 to grow, and the larva commences feeding on the corn roots. 

 While the roots are small they commence at the end and 

 work along the root; after the roots are larger they work 

 into the roots. They cause the ears to l^e small and when 

 numerous can kill out the entire plant. They get their 

 growth by the middle of July or first of August, pupate, 

 and spend a few days in the pupal stage, and issue as adults 



Fig. 139. — Western corn-root worm (Diabrotica loiigicornis) : o, beetle; 

 h, larva or root worm; c, enlarged leg of same; d, pupa — all enlarged; 

 c, more enlarged. (Chittenden, Div. Ent., T'. S. Dept. Ag.) 



in autumn. There is a single brood in a year. Rotation of 

 crops serves as an almost absolute means of pre\ention of 

 injury from this species. It was most troublesome in the 

 corn regions of Illinois where corn was planted year after 

 year on the same ground. 



The other species with this habit is also destructive to 

 corn ( Diahrotica 12- inmctat a) . It is known as the Southern 

 corn-root worm. It is also troublesome to some other 

 plants, so that its control is not so easy or certain. 



The elm-leaf beetle, an introduced species which has been 

 a very serious pest in the Atlantic States, has recently 



