IX] 



MOSQUITOES AND MALARIA 



137 



Among habits affecting the conditions of malarial dissemina- 

 tion may be mentioned the predilection of particular species for 

 particular kinds of breeding place. Some species are essentially 

 stream breeders and are even adapted by their habits, and 

 probably to some extent by structure, to prevent themselves 

 being carried away by flood conditions. An example of a species 



Fig. 42. Breeding places of Anophelines. Railway cutting at Kurunegala. 

 The water course flowing on each side of the permanent way supplying 

 the engines with water. These channels are blocked with weeds, from 

 amongst which larvae of A. culicifacies and A. rossii have been taken. 

 After Bahr (from the Tropical Diseases Bulletin). 



having this habit is A. {Myzomyia) listoni {M. christophersi 

 Theobald), which swarms in the streams of the sub-Himalayan 

 terai, and is largely responsible for the high prevalence of 

 malaria in these regions. Another example is A . (Nyssorhynchus) 

 willmori, a species which is very difficult to eradicate, because 

 of its power of breeding freely in the small streams of Malay 



