DISEASE BEARING AM ERIC AX MOSQUITOES 



27 



The eggs of Anopheles may be distinguished from those of 

 Culex and some other common mosquitoes by the fact that the 

 former are laid singly and are supported on the surface of the 

 water by lateral air-spaces, while the latter stand vertically 

 in closely-packed rafts. 



Fig. 25. — Larva of Anopheles. (Afti r 

 U. S. Public Health Service.) 



Fig. 26. — Larva of Culex. (After 

 U. S. Public Health Service.) 



Anopheline larvae may be distinguished from the larvae of all 

 other genera by the fact that the head is much smaller than the 

 thorax, that they have virtually no breathing tube and that they 



Fig. 27. — Pupa of Anopheles Fig. 28. — Pupa of Culex pipiens. 

 punctipennis. (After Howard, (After Howard, Dyar and Knob. 

 Dyar and Knab.) 



lie horizontally under, but close to the surface, of the water, 

 very much like a basking pike. All other common American 

 larvae, on the other hand, have the head larger than the thorax, 

 have a long breathing tube and hang head down at an angle of 

 about 60 degrees from the plane of the water surface. Upon 

 being frightened, Anopheles larvae usually dart about parallel 

 to the surface, while other larvae usually dart downward. 



