FIELD BOOK OF INSECTS. 



Yellow fever is transmitted by calopus, a tropical and 

 subtropical species of a subgenus, or separate genus, 

 Aides. This mosquito has also been called Stegomyia 

 fasciata. For the most part, the species of Culex have 

 unspotted wings; the palpi of the female are short, the 

 beak not appearing to have three nearly equal prongs. 

 The adults usually hold their bodies parallel to the surface 

 on which they rest, the beak being at an angle. The 

 larval breathing siphon is long and the larvae hang head- 

 down from the water's surface film. The eggs of Culex, 

 in a limited sense, such as those of the common, rain- 

 barrel C. pipiens, are laid in a floating, raft-like mass. 

 Those of what are now called Aedes, such as the common 

 salt-marsh mosquito with banded legs, A. sollicitans, 

 may be laid singly or in little masses in the mud of low 

 ground, or on the surface of the water, sinking to the 

 .bottom and usually passing the winter in that stage. The 

 eggs of A. canadensis commonly hatch in woodland pools 

 before the weather moderates. 



Wyeomyia smithii breeds in the leaves of pitcher plants 

 (Sarracenia). "Larvae may be found at all times of the 

 year, the winter being passed in that stage, sometimes 

 active in mild weather, sometimes frozen solid" (Smith). 

 Even the female does not bite. 



The pupa? of mosquitoes are humpbacked wrigglers or, 

 rather, "flappers," which breathe by means of a pair of 

 trumpet-shaped siphons on their back. They are active 

 throughout pupal life but do not usually move unless dis- 

 turbed. The larvae and pupae really breathe atmospheric 

 air, for they stick their breathing siphons just out of the 

 water. Kerosene, spread on the water, prevents them 

 from getting to the air, hence they smother. Furthermore, 

 the kerosene may corrode their tissues. However, the 

 best way to combat mosquitoes is to prevent their breed- 

 ing. Put fish in all pools which cannot readily be drained; 

 keep the edges of streams and ponds sharp so that fish 

 can collect all the eggs, larvae, and pupae; drain swamps and 

 useless pools; bury tin cans and the like; and fill up all tree 

 holes. I hope this will 'never be completely done in my 

 lifetime. I would rather stand a few mosquitoes than 

 have all my collecting places for aquatic insects spoiled. 



240 



