i8o 



remains to be shewn that dnophtlinae, 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 

 Ano-phelinae 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 Culicinae. 

 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 Anophelines, 

 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 Ano- 

 phelines (larvae), which may find an opportunity of 

 becoming infected later. 



'DOMESTIC' AND 'WILD' ANOPHELINES 



Ano-phelines are mostly found in association with 

 native dwellings where there is abundance of food 

 (blood). Anofhelines are also generally abundant 

 where cattle are kept. 



Certain species are distinctly ' domestic ' in their 

 habits, e.g., Mym. rossi, Pyr. costalis, Nyss. stepbensi, 

 and others. They are found resting in the daytime 

 in the thatch of huts, and they breed close at hand 

 in the nearest puddle. They may, however, fly up to 

 half a mile if there are no breeding places closer. 



Other species are not peculiar to houses, but are 

 also found breeding in streams and pools in the jungle 

 far from habitations. Such species are Nyss. maculatus, 

 Nyss. theobaldi. 



