N 



AQUATIC INSECTS 



Fig. 207. — Diving beetle, Coptotomus interroga- 

 tus: I, larva (from Wilson); 2, adult. 



torn, breathing by means of its tracheal gills which trail off 

 from the sides of the body. It is usually a half inch long. 



Fig. 208. — Diving beetle, Cyhister: i, larva (from 

 Wilson); 2, adult male; 3, underside of his front 

 tarsus, showing the roughened surface which is 

 pressed against the back of the female in mating. 



269 



A 



