AQUATIC INSECTS 



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Fig. 211. — Larvae of whirligig beetles: i, Gynnns 

 (from Kellogg after Schiodte); 2, Dineiites (after 

 Wilson) . 



out fringes; otherwise the larvse of the two genera are 

 similar. ' 



Pupae. — When fullgrown the whirligig larva crawls out on a 

 moist bank and its gills shrivel up except for the last three 

 pairs, which persist and seem to be used in locomotion. The 

 pupating Dineutes observed by Wilson made pupal cases 

 from pellets of earth stuck together with" saliva. The full- 

 grown larva selected a reed or grass blade near enough to the 

 ground so that it could reach the earth, then hanging itself 

 up by its posterior hooks it built a case round itself, repeatedly 

 stretching downward to grasp a mouthful of dirt, sometimes 

 taking a stick or leaf with it. When finished the pupal case 

 is about half an inch long and the full-grown larva is folded 

 up in a C-shape within it. 



Water scavenger beetles, Family Hydrophilidae. — In the 

 same protected water with the dytiscid beetles are other large 



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