10 



at the surface, which it does most of the time, it lies with its body 

 parallel with the surface, and not hanging down, as does the Culex 

 wiggler. The pupae of both forms are shown in fig. 8, and need not 

 be described. 



Breeding places of malaria-bearing mosquitoes. — The breeding places 

 of the harmless mosquitoes are more numerous and more varied than 

 the breeding places of the malarial mosquitoes. Anopheles, however, 

 are found under many diverse conditions. They are found, as stated, 

 in still side pools of small streams, in the swampy pools at the margins 



Fig. 



-Anopheles crucians. Enlarged (author's illustration). 



of larger ponds, in stagnant Avater in ditches, in the beds of old canals, 

 in the still water at the sides of springs, and occasionally, though 

 rarely, in old horse troughs. They are perhaps more frequently found 

 in such situations as described when a certain amount of green scum 

 has accumulated, and it is upon the spores of the water plants consti- 

 tuting this green scum, as well as upon other very small objects float- 

 ing on the surface of the water, that they principally feed. 



Measures to be taken to prevent malaria.— To prevent malarial mos- 

 quitoes from breeding in a given vicinity, one should be prepared to 



155 



