THE NATURAL HISTORY OF BOMBAY MALARIA. 413 



ed for the breeding of N. stephensi. A few months ago when I 

 examined these filters I found every one breeding thousands of 

 these mosquitoes, and by using a muslin net which I drew along 

 the edges of the filter beds I was able to collect a large number of 

 them. At the time the larger reservoir which is underground, 

 was undergoing repairs and was empty ; but in a number of little 

 pools of water on the floor I found many specimens of N. stephensi. 

 In Malabar Hill too I found the same mosquito breeding in the 

 reservoirs and filters in spite of the fact that they are under cover. 

 One of the filter beds which has been out of use for a long time on 

 account of leakage, had its cushion well positively swarming with 

 larvas in spite of the presence of fish, evidently of a species which 

 did not fancy a diet of mosquitoes. I may as well make it clear 

 while speaking of the reservoirs and filter-beds, that the presence 

 of mosquito larvas in these places is no danger to the City in 

 general but only to the unfortunate people who have to live in the 

 immediate neighbourhood. Both at Mazagon and Malabar Hill 

 the vicinity of the waterworks has long been known to be malari- 

 ous and this has usually been ascribed to leaking water. Probably 

 this has been one cause, but there is no question that the reservoirs 

 and filters themselves are a source of considerable danger to the 

 areas immediately adjoining them. 



Foreshore Pools. 



Foreshore pools existing at Colaba and on the west of Nepean 

 Sea Road at Malabar Hill are also a source of danger owing to the 

 breeding of Nyssorhyuchus stepjiensi. There are two places in 

 Colaba, one on the east and one on the west coast, where I have 

 found this mosquito breeding. One of these places is a small Bay 

 just to the south of Bassoon Dock, and the other is a little Bay just 

 at the back of the Colaba Post Office. In addition to these places 

 it may be mentioned that Oulex mosquitoes and Myzomia rossi can 

 be found breeding all along the foreshore of Upper Colaba, but so 

 far N. stepliensi appears to be absent — probably because no perma- 

 nent breeding places for the insect exist there, all the wells and 

 cisterns being carefully covered. Along the foreshore of Nepean 

 Sea Road there are a great number of rocky pools which usually 



