296 



COMPARATIVE ZOOLOGY. 



Fig. 265.— Metamorphosis of an Hemipter, Water-boatman (Notonecta). 



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

 are nearly all vegetarian. Each family produces charac- 

 teristic sounds (stridulation). The representative forms 



Fig. 266 — Seventeen-year Cicada (Cicada septendecim)~ a, pupa; b, the same, after 

 the imago, c, has escaped through a rent in the back ; d f holes in a twig, where 

 the eggs, e, are inserted. 



