THE NATURAL HISTORY OF BOMBAY MALARIA. 403 



Anopheles Larvce. 



Tt is also possible to distinguish between the larvae of these 

 different species of anopheles, and this is rather an important point, 

 because we can usually find and capture mosquito larvae more 

 easily than adult insects, which are often rather difficult to catch. 

 Of course, it is a very simple matter to breed out mosquitoes from 

 any larvae that we have obtained, but it is very useful to be able 

 to recognise the species to which they belong without going to all 

 this trouble. 



Captain Liston in the paper to which I have already alluded, 

 pointed out that a knowledge of the habits of mosquitoes soon 

 teaches us that each species usually selects particular types of 

 breeding places. This is quite true when we are dealing with 

 natural breeding places, but we cannot absolutely depend upon such 

 a rule in Bombay, where almost all the breeding places are of an 

 artificial nature. Thus the five species of anopheles to be found in 

 Bombay — all make use of wells for breeding places — and although 

 it is possible to recognise the larvae of N. jamesi, M. culicifacies and 

 M. harbirostris with the naked eye, it is impossible to tell the larvae 

 of N. stephensi apart from those of M. rossi, except by the use of 

 the microscope. We may lay down, however, certain general rules 

 which will help us in many cases. Thus when we find anopheles 

 larvae in foul wells, puddles of dirty water or in liquid sewage, we 

 may be almost certain that we have to do with M. rossi and not 

 with the other and more dangerous species. If we find anopheles 

 larvae breeding in the weedy part of a tank, among the grass close 

 to the edge, it is very probable that they will turn out to be N. 

 jamesi, and we can be almost certain of this when they have a 

 slightly brownish colour and present a rather hairy appearance. 

 i¥. harbirostris larvae may be found in the darker and deeper parts 

 of such a pond especially where it is overshadowed by trees, and it 

 is very common in some of the large open wells in the northern 

 part of the island, The larvae are generally very dark in colour, 

 often almost black, and they usually have two whitish marks 

 across the back. They do not taper so much towards the tail as 

 many of the other larvae do, the smaller ones often appearing to be 

 almost the same width from the thorax downwards. The larvae of 

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