3 MISC. PUBLICATION 336, U. S. DEPT. OF AGRICULTURE 



The food of mosquito larvae consists of minute plants and animals 

 and fragments of organic debris, which the larvae strain from the 

 water by the action of their mouth parts. Barber (£, 3) reared the 

 larvae on pure cultures of various organisms, and concluded that 

 the presence of living food organisms was necessary for any consid- 

 erable growth. Hinman (56) has suggested that materials in solu- 

 tion and colloids in suspension in the breeding waters may play a part 

 in larval nutrition. A discussion of the food of anopheline larvae 

 is given in the notes on Anopheles quadrimaculatu-s. 



With the fourth molt the pupa appears. The pupal stage (fig. 4) 

 is also aquatic and is a period of marked transformation, during 



Figure 4. — Pupa of Culex pipiens. (Howard, Dyar, and Kiiab.) 



which the adult insect is formed. The imago usually emerges after 

 about 2 days. 



The length of life of adult mosquitoes under natural conditions 

 is difficult to determine, but for most of the southern species it is 

 probably only a few weeks during the summer months. Some of 

 the northern species of Aedes that emerge early in the spring ap- 

 parently live much longer. Daily observations on abundance follow- 

 ing the emergence of a large brood of certain species of Anopheles 

 (M2) and Aedes have shown a marked reduction in numbers within 

 2 weeks. The southern house mosquito probably lives longer than 

 this, and the yellow-fever mosquito may live, on an average, a month 

 or more, with a maximum of several months. 



