THE NATURAL HISTORY OF BOMBAY MALARIA. 399 



species of anopheles, N. stephensi, and if we can devise efficient 

 measures for reducing the numbers of this mosquito, we shall in all 

 probability greatly lessen the incidence of malaria among the 

 population . 



This fact is of great importance, for there are many different 

 species of mosquitoes in Bombay, which swarms with Culex and 

 Stegomyia and Anopheles : and it is only when we clearly realize 

 that only one mosquito is really responsible for the spread of malaria 

 in the greater part of the city that we can understand why it 

 should happen that there is often very little of the disease in places 

 where there are millions of mosquitoes. I wish to lay stress upon 

 this point, because there are many people who fail to understand 

 how mosquitoes can possibly be concerned in the spread of malaria 

 when their own experience is that there is often little malaria 

 where there are many mosquitoes and much malaria where there 

 are few mosquitoes. 



In Bombay the mosquitoes concerned in the spread of malaria 

 represent only a fractional proportion of the total insects. This 

 being so, those who wish to avoid malaria, or whose duties render it 

 necessary to attempt the reduction of the disease, must be in a 

 position to recognise the dangerous species. 



Although it is very easy to distinguish between Anopheles and 

 Culex or Stegomyia mosquitoes, it is by no means so easy to 

 recognise the different species one from another or to separate the 

 dangerous anopheles, N. stephensi, for instance, from the harmless 

 anopheles, M. rossi. 



As a matter of fact, it often happens that these two species 

 are confused the one for the other. This would not matter so 

 much, if it were possible with the funds usually allotted for the 

 purpose to destroy or reduce the numbers of every kind of mosquito. 

 Unfortunately the amount of money that a city like Bombay is 

 prepared to spend upon this kind of work at present will not allow 

 of this, so that it becomes a matter of importance that when anti- 

 mosquito measures are undertaken for the avowed object of* 

 reducing malaria, money should be spent in such a way as to 

 achieve its purpose, rather than in the mere destruction of a 

 certain number of mosquitoes, many of which have nothing to do 



