386 



SOME REPRESENTATIVE INSECTS 



mosquito (c/. p. 207). Since then the structure and Hfe histories 

 of mosquitos the world over have been exhaustively studied. 

 The mouth parts of the adult female are adapted for piercing 

 the human skin and sucking blood, which is prevented from 

 coagulating by the saliva. The mouth parts of the male cannot 

 thus pierce the skin, and the males feed, if at all, upon the nectar 

 of plants and other available fluids. As females may be fed upon 

 bits of banana in the laboratory, it is supposed that they some- 

 times feed as do the males. But in addition to such food the 

 female must attack some warm-blooded animal, since it is impossi- 

 ble for her to mature the eggs without such a meal of blood. 



Fig. 199. — Life cycle of the mosquito, Culex, one of the Order Diptera. 



1, egg; 2 and 3, larval stages; 4, pupa; 5, emergence of adult from pupat skin; 6, adult. 

 (From Bulletin No. 348, New Jersey Agr. Exp. Sta.) 



It has been found that the malaria parasite is seemingly restricted 

 to mosquitos of the genus Ariopheles and that the genus Stegoniyia 

 harbors the parasite of yellow fever. The most common genus of 

 temperate latitudes is Culex, which does not serve as a host to either 

 of these parasites. The species of the genus Culex (Fig. 199) lay 

 their eggs fastened together in little rafts that float upon the sur- 

 face of the water. The larvae that hatch from these eggs are 

 the " wrigglers " commonly seen in rain barrels and small bodies 

 of water where they hang suspended from the surface film by 

 the tube at the posterior end of the body through which air is 

 admitted to the tracheal system. If disturbed they wriggle down- 

 ward and fasten themselves upon the bottom or some submerged 

 object, but soon they float upward and again hang from the sur- 



