CHAPTER XVI 

 BLISTER-BEETLES 



The blister-beetles are elongate, long-legged insects which 

 in the adult stage frequently attack cultivated crops in swarms. 

 They devour the foliage and blossoms and frequently defoliate 

 the plants. They usually feed in colonies moving slowly across 

 the field and destroying the plants as they go. 



As far as known, the larv?e of blister-beetles feed on grass- 

 hopper eggs but the life history of most species has not been 

 studied. C. V. Riley has given a good account of the early 

 stages of the striped blister-beetle, but even in the case of this 

 species much remains to be learned. About tw^o hundred 

 species of blister-beetles are known to occur in America north 

 of Mexico. Less than a score of these have been recorded as in- 

 jurious to cultivated plants, but it is quite probable that many 

 of the others may on occasion become destructive. 



Most blister-beetles contain a substance, cantharidin, wdiich 

 has the property of blistering the skin. The spanish-fly of 

 commerce consists of the dried bodies of certain species of 

 blister-beetles. 



The Striped Blister-Beetle 



Epicauta vittata Fabricius 



The striped blister-beetle has long been known as an enemy 

 of the potato, on which it was formerly more destructive than 



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