136 



APPLIED ENTOMOLOGY 



called cantharidin, which when applied to the skin, produces blisters. 

 The bodies of these species, powdered, are used in medicine under the 

 name ''cantharides" or ''Spanish flies," for blistering purposes. 



A dozen or twenty kinds of Blister beetles, averaging from half 

 an inch to over an inch in length are more or less serious pests as adults, 

 feeding during the summer or fall on foliage and blossoms, various vege- 



FiG. 128. — Adult Blister Beetles: a. Black Blister Beetle (Epicauta pennsylvanica 

 De G.); b, Ash-gray Blister Beetle {Macrohasis unicolor Kby.) ; c, Striped Blister Beetle 

 (Epicauta vittata Fab.) ; all about natural size. (Modified from U. S. D. A. Bulletins.) 



tables and ornamental plants being attacked. Vegetable crops are 

 sometimes seriously affected. The larvae on the other hand, feed on the 

 eggs of various species of grasshoppers and are therefore beneficial. 

 The adults are not easily controlled as they are rather resistant to arseni- 

 cal poisons, and as they fly freely, it is difficult to reach them with contact 

 insecticides. In cases where stomach poisons can be applied, arsenate 



of lead, taking about 4 lb. (if the 

 paste be used) to 50 gal. of water, 

 has proved the best treatment. 

 Where this cannot be done, hand- 

 picking, and screening valuable 

 plants with netting, may be 

 resorted to. 



RHYNCHOPHORA (Snout Beetles) 

 The snout beetles are included 

 in several families. Some are 

 called curculios, weevils, and bill- 

 bugs, and those of one family, the 

 larvae of which work in the bark 

 and wood of trees, are called Engraver beetles and also bark borers. 

 Over twenty-five thousand species of Rhynchophora are known (Fig. 129). 

 Except for this last named famfly, most snout beetles feed on fruits, 

 nuts, etc., though a few attack stems and leaves. The white, nearly 

 always footless larvae, also feed for the most part on such materials, and 

 a number are very destructive and therefore important pests. 



Fig. 129. — Examples of adult Snout 

 Beetles showing differences in the develop- 

 ment of the snout. About twice natural 

 size. {Original.) 



