THE BEETLES: ORDER COLEOPTERA 137 



tions, which are being cut over, the leaving of a few stalks 

 as trap plants to attract the adult beetles when they lay 

 their eggs has been found effective. These trap plants, 

 of course, are to be destroyed often enough to prevent the 

 eggs from hatching. 



A much more familiar and widely distributed leaf beetle 

 is the common Striped Cucumber Beetle, which is found 

 practically everywhere that cucumbers, melons, squashes, 

 or related plants are grown. These insects pass the 

 winter as adults under such shelter as they may find, and 

 in spring feed ravenously upon the young cucumber or 

 other plants. They also deposit their eggs about the 

 roots of these plants, and the eggs shortly hatch into 

 slender larvae that feed upon the roots. In this way, the 

 beetles not only threaten the crop in their adult state, but 

 they often do a more serious, though less recognized, 

 damage in their larval state. These are among the most 

 difficult of all pests to keep in check. A few hills may be 

 covered with netting or cloth. The liberal use of refuse 

 tobacco powder is generally also an efficient protection. 

 The complete destruction of all squash, cucumber, melon, 

 and pumpkin vines as soon as the crop is gathered is a 

 very desirable preventive measure. If these are left, the 

 adult beetles find abundant food up to the time they go 

 into their hibernating quarters, and consequently are in 

 better condition to survive the winter. 



A closely related insect, which at times has been ex- 

 ceedingly destructive, is the Northern • Corn Rootworm. 

 This is a small beetle, about the size of the Cucumber 

 Beetle, but of a uniform pale green color. In the larval 

 state it feeds upon the roots of com and so weakens, the 

 plants that the development of the crop is greatly 

 checked. The larvae change to the pupa state and 



