296 



COMPARATIVE ZOOLOGY. 



PIG. 265 Metamorphosis of an Heiuipter, Water-boatman (NotonecM). 



vse and pupae are active, and resemble the imago. They 

 are nearly all vegetarian. Each family produces charac- 

 teristic sounds (stridulation). The representative forms 



Fm. 266. Seventeen-year Cicada (Cicada septendecim) : a, pupa; b, the same, after 

 the imago, c, h;is escaped through a rent in the back ; d, holes in a twig, where 

 the eggs, e, are inserted. 



