28 



MOSQUITO ERADICATION 



Anopheles pupae are larger in the antero-posterior direction and 

 narrow laterally, while Culex pupae are short and broad from side 

 to side. The breathing siphons of Anopheles pupae are short 

 and trumpet-like, while those of Culex larvae are long and 

 narrow. 



As a general rule, the Anophelinae prefer natural breeding 

 places to artificial ones and manifest an aversion for sewage- 

 polluted water and for brackish water, although they are occa- 

 sionally found in such waters. Their food, in the larval state, 

 consists mainly of algal spores, minute insects or crustaceans, 

 etc. Some authorities state that . they become cannibalistic 

 when their usual food becomes scarce. 



A. QUADRIMACULATUS SAY 



Of the three common American malaria-carrying mosquitoes 

 it is believed that A. quadrimaculatus Say is probably responsible 

 for more harm than either of the other two. 



A. quadrimaculatus may be distinguished from the other Ameri- 

 can Anopheles by the fact that it is 

 brownish in color and has from three 

 to five — but generally four — black- 

 ish spots on the second and fourth 

 wing veins, whence its name is 

 derived. These spots are patches 

 of black scales. 



A . quadrimaculatus passes the win- 

 ter as an adult female, in cellars, 

 forests, barns and other sheltered 

 places. When warm weather comes 

 in the spring, these females emerge 

 from their hiding places and deposit 

 their eggs. From 50 to 75 are laid 

 at a time. If the weather is favorable, the larvae emerge in 2 

 or 3 days and begin feeding. In from 4 to 6 days of warm 

 weather — or much longer in cool — the wrigglers transform into 

 pupae; 2 or 3 days more and the adult emerges. Breeding 

 appears to be as continuous from spring to autumn as tempera- 

 ture and other conditions will allow. 



While the favorite breeding-place of A. quadrimaculatus is 

 grass-bordered pools, ponds, pot-holes, etc., it has been reported 

 to breed in slowly moving streams. It will also, on occasions, 



Fig. 29. — Anopheles quadritnacu 

 latus, female. 



