268 



SANITARY ENTOMOLOGY 



These eggs are laid singly, a small number at a time, upon the surface of 

 the water. 



Anopheles punctipennis Say (fig. 49a) has an elongate fusiform Gggi 

 reticulate ventricallj^, finely granular dorsally. The floats are large, 

 extending nearly to the apices, closely approximated medianly on the 

 dorsal surface, arcuately produced at the sides to the apical fourths, 



Fig. 48. — Eggs and larvae of Culex. Enlarged. (Howard.) From U. S. Dept. Agr., 



Farmers' Bull. 155, fig. 5. 



widely separated on the ventral surface, and showing only on middle 

 third of sides. The eggs are laid singly or in small groups upon the 

 surface of the water. 



Anopheles quadrimaculatus egg is shown in fig. 49b. 



THE LARVAE AND THEIR HABITS 



All mosquito larvas are aquatic. By far the most of the larvae occur 

 in small deposits of water, although certain species occur in large bodies 



Fig. 49. — Eggs of malaria mosquitoes: a, Anopheles punctipennis; b, A. quadrimacula- 

 tus; c, A. crucians. (After Howard, Dyar and Knab.) 



of water. Those species which lay their eggs on the ground in dry 

 regions, hatch as soon as rains occur, and the larvae go through a very 

 rapid development. Such species show a rather marked periodicity in 

 broods. Species which have abundance of water breed continuously 

 during the warmer seasons. One is apt to find mosquito larvse wherever 

 water occurs. 



The food of the larvae varies, but usually consists of the minute forms 



