246 



ELEMENTARY ZOOLOGY. 



adapted to biting and they undergo a complete meta- 

 morphosis. The larvae are often known as "grubs." 

 A few beetles prey upon hurtful insects. For example, 

 the lady-bug beetle devours great numbers of the scale 

 insects, which are proving such a pest to orchards of 

 various kinds. More commonly, however, they are 

 vegetable feeders, and there is no form of vegetation 



FIG. 92. The hessian fly (Cecidiomya destructor). From Standard Natural 

 History, o, adult; b, larva; c, pupa; d, larva in position on stalk of wheat. 



Questions on the Figure. Give names to all the structures appar- 

 ent in the adult. In what stage does the insect do its damage? 

 What is its economic importance? What is the origin of the com- 

 mon name? 



which is not attacked by them. The potato-beetle 

 devours the leaves of the potato plant ; the curculio, and 

 other forms, lay their eggs in fruits, such as plums, 

 apples, peaches, and the like, and the grub burrows about 

 getting its living as the fruit ripens; the cotton-boll 

 weevil bores into the young cotton fruit and injures or 

 destroys the growing fibers, robbing the cultivator of 

 millions of dollars annually ; many of the weevils attack 



