COLEOPTERA 123 



gish movement. Some forms will blister the slrin if 

 crushed on it and this fact makes them of some value for 

 medicinal purposes. These species supply the Cantharides 

 or "Spanish-fly" of commerce. They feed on plants. The 

 old-fashioned potato beetles are blister-beetles. Some kinds 

 feed on clover and alfalfa, at times to such an extent as 

 to be pests. Larvae of blister-beetles have a curious and 

 very complex development. First they are active and 



FIG. 90. Asparagus Beetle, FIG. 91. A Blister-beetle or 



type of Chrysomelidoe. Oil-beetle, Meloe, sp. (Me- 



Enlarged greatly. loidce). Twice natural size. 



move about to search for the insect eggs upon which they 

 feed. Later they attack different kinds of insects and 

 become parasitic. They then become fleshy and sluggish. 

 Some of them are of importance because they destroy 

 grasshopper egg masses. 



77. Tenebrionidae. This family includes a considerable 

 number of species, few of which are either important or 

 conspicuous. The common name Darkling-beetles has 

 been given to the family. The larger members resemble 

 superficially the ground beetles, but have antennas larger 

 at the tip than at the base and have only four joints on 



