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remain where they were developed, and in the 

 native huts where they find abundant food. 



That various accidental modes of distribution 

 occur is equally certain, e.g. : — 



1. On trains, boats, and even ocean-going 

 steamers, they may be carried long distances, e.g., 

 from West Africa and South America to England, 

 but it remains to be shewn that Anophelinae, thus 

 introduced, ever effect a permanent habitation, 

 even when the removal by this means is from one 

 portion of the tropics to another. 



2. Locally, streams and canals may carry 

 larvae and ova long distances, perhaps miles. 



3. Winds. — The maximum distance that the 

 Anophelinae can be carried in this way is quite un- 

 certain. Nearly all of the excessive distances that 

 have been given as- possible flights refer to Culex. 

 It appears certain, moreover, that the Anophelinae 

 dislike wind and seek shelter from it. 



4. Trees, Plantations, ' Bush ' Jungle. — These 

 elements undoubtedly hinder the flight of Ano- 

 phelines, and, on the contrary, open spaces promote 

 their diffusion. It is necessary to bear this fact in 

 mind, where a belt of jungle screens off a source 

 of Anophelines (larvae), which may find an oppor- 

 tunity of becoming infected later. 



' Domestic ' and ' Wild ' Species of Anopheles 



Anophelines are mostly found in association 

 with native dwellings where there is abundance of 

 food (blood). Anophelines are also generally abun- 

 dant where cattle are kept. 



Certain species are distinctly ' domestic ' in 

 their habits, e.g., Mym. vossii, Pyr. costalis, Nyss. 



