BLISTER BEETLES 



199 



sylvanica DeG.)- The first named of these beetles is grayish in 

 color, and the second shining black. These beetles are striking in 

 appearance, have rather long legs, with a somewhat elongated 

 thorax or neck (Fig. 216). The bodies are long, straight-cut, and 

 are said to cause blisters when crushed on the skin. A near rela- 

 tive found in Europe is known as the " Spanish fly" and is used in 

 medicine. The adult beetle emerges in the spring. 



Injury. Occasionally these beetles are extremely injurious to 

 leguminous plants, although they may be regarded as general 

 feeders. They work also on sugar- 

 beets, potatoes, various flowering 

 plants, and trees and shrubs. 



Benefit. These insects have the 

 redeeming feature that when hatched 

 the small, long-legged larvae imme- 

 diately run about searching for 

 grasshopper eggs in the field. Upon 

 these they feed. A little later the 

 skin of the larva is shed, together 

 with the long legs of the first form of 

 larva, and we find them in the second 

 stage possessing very short rudimen- 

 tary legs. This form is found in grass- 

 hopper nests feeding upon the eggs. 



Control. These beetles are quite 

 resistant to arsenicals, but can be 

 driven off of a crop by applying 

 Paris green or arsenate of lead sprays. 

 When occurring on trees, they may be jarred off on sheets and 

 destroyed by being thrown into kerosene. This same method 

 may perhaps apply in the case of some other plants if the 

 attack is not too general. The usual arsenical sprays applied 

 to potatoes will serve to keep them in check upon these plants. 

 A mixture of arsenate of lead, three pounds hi fifty gallons of 

 water, if sweetened with cheap molasses or syrup, makes a fairly 

 effective spray. 



When alfalfa or other crop is seriously attacked, any remedial 

 measure, to be effective, should be applied at once. Alfalfa may be 

 sprayed with arsenicals as above indicated, in which case more 

 than one application may be necessary, and the sprayed portions 

 should not be used for hay. 



FIG. 216. A blister beetle. 



