GENERAL ZOOLOGY 



plants ; in fact, both sexes in the past history of the race 

 were probably, and are still, to some extent, plant-feeders. 



The common mos- 

 quito of the Missis- 

 sippi valley and the 

 East is Cu' lex pun' gens 

 (Fig. 39). The female 

 lays her eggs in irreg- 

 ular masses, contain- 

 ing over two hundred 

 eggs, on the surface 

 of the water early in 

 the morning. Within 

 a day they hatch, and 

 the larva? are the fa- 

 miliar, active creatures 

 known as "wrigglers." 

 The next to the last 

 Enlarged, somite bears a long 

 s., United respiratory tube 



of Entomology) 



A, egg-mass; -B, larva; C, pupa 



FIG. 39. Development of Mosquito. 

 (After Howard, Bulletin No. 25, N 

 States Department of Agriculture, Division througb wh ; ch the 



larva breathes air when 

 at the surface ; the last 

 somite is provided with four flaps (tracheal gills) which act 

 as organs of respiration when the larva is beneath the surface. 

 In addition to these methods of obtaining air, the skin is 

 capable of absorbing oxygen, and a network of trachea lines 

 the posterior part of the alimentary canal, so that oxygen 

 may be obtained from the water taken in at the anal opening. 

 The Iarva3 feed on small particles of decaying matter in the 

 water, thus being useful as scavengers. After several molts 

 and a life of about a week, if the weather is warm they then 

 pass into the pupal stage, breathing by means of two air- 

 tubes arising from the thorax. In about two days the pupal 



