AQUATIC INSECTS 



Culex. — The genus Culex, common house mosquitoes, can 

 be recognized b}^ their hump-backs and their habit of stand- 

 ing with their bodies nearly parallel to the surface. Their 

 wings are plain colored, never spotted like those of Ano- 

 pheles (Fig. 231). None of this genus is known to carry 

 either malarial or yellow fever organisms. 



They lay their eggs on the surface of the water, each egg 

 standing upright but glued to its neighbors so that the whole 

 cluster makes a floating raft (Fig. 232, i). The eggs hatch 

 within about three days, depending on the temperature and 

 the species. 



Fig. 232. — ^Water phases of mosquito life: i, 

 Culex eggs on water surface; 2. larva; 3, pupa; 4, 

 Anopheles eggs at surface and egg enlarged shomng 

 floats at sides; 5, larva; 6, pupa. 



Anopheles. — Anopheles or "malarial mosquitoes" can be 

 distinguished by their straight bodies which lack the "round- 

 shouldered hump" of Culex, their black and white spotted 

 wings, and their habit of resting with the hind end of the 



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