THE INSECT WORLD. 



221 



plants. Or they may be thoroughly sprayed with the Bordeaux 

 mixture immediately after being set out. 



Of somewhat larger size and more slender, graceful form are 

 the species of Systena, and of these, kS. blanda, the ' ' pale-striped 

 flea-beetle," has become best known by reason of its injury on a 

 great variety of plants, including sugar-beets. As with the other 

 " fleas" it is injurious in the beetle stage only, and, as a rule, in 

 early summer on young plants. I have seen it ruin an entire 

 field of carrots, and have found it on melons, potatoes, beets, and 

 pig-weed in equal abundance. Its life history has not been pub- 

 lished, but its larva is said to feed upon corn-roots. This is cer- 

 tainly not universally true, and its native food-plant in the early 

 stages remains to be ascertained. As with other leaf-feeding 

 forms, we are referred to the arsenites; or, as a means of protection 

 only, to air-slacked lime, which will drive the beetles to wild 

 plants, leaving the lime-dusted crop free. 



In the genus Phyllotreta we find another series of small species 

 not exceeding one-eighth of an inch in length, ordinarily black in 

 color, with yellow stripes or 



spots on the wing-covers. The Fig. 221. 



most common species in the 

 East is the ' ' wavy-striped flea- 

 beetle," P. vittata, in which 

 there is a distinct yellow stripe 

 through the middle of each ely- 

 tron. The adults feed upon the 

 leaves of cabbage, radish, mus- 

 tard, and others of the cruciferse, 

 while the larvae live as miners 

 in the tissues of the same plants. 

 In dealing with this species 

 the important points are clean 

 culture and keeping down all 

 cruciferous weeds. If in addi- 

 tion all crop remnants are promptly gathered and destroyed, no 

 serious danger need be apprehended. 



Following the flea-beetles is a series of very curious, somewhat 

 wedge-shaped insects, the Hispidcs, in which the antennae are 

 thickened, and the elytra, or wing-covers, broaden to the tip, 



Striped flea-beetle, Phyllotreta vittata.- 

 a, larva ; b, adult. 



