h}2 A Monograph of Culicidae. 
wide ; the interesting point. about the latter was that there was 
no vegetation of any sort in the water except some old sea- 
weed. Any collection of water in the country seems to do for 
their breeding in, especially when it is more or less thickly 
grown with algae and other water plants. On the Morne, in St. 
Lucia, they were found by Major Will in large numbers in holes 
caused by the removal of boulders, and as these were quite 
recent some had no vegetable growths in them at all. In 
Georgetown, Demerara, I found them in great numbers in the 
large canals that run along the middle of many of the streets. 
In Dominica their breeding-grounds were very interesting. Dr. 
Nicholls on my arrival there told me that there were cases of 
malarial fever at one part of the town, and on searching this 
area the larvae were found in the Roseau River, in a backwater 
with a gentle flow of water through it. They were at the side of 
this in some short grass and were found to within a yard of the 
main current. I have never found them in water-barrels, tubs, 
tanks, wells, or other collections of a similar nature in towns. 
They are not found in Barbados, though water taken from a 
swamp there acted as a suitable medium for their development 
in St. Vincent (‘ Brit. Med. Journ. Jan. 25.02). The highest 
altitude they were found at was on the Morne, St. Lucia, 800 feet 
high. 
“The larvae die quickly under artificial cultivation if the 
water is allowed to become foul. This stage lasts fifteen to 
eighteen days and the pupal stage two days. 
“The adult insect is not in any sense of the term a domestic 
or house mosquito. They come in to feed just as it is getting dark 
and leave again in the mornings as it gets light. Searching 
many native huts by day invariably gave negative results. That 
they do come in at nights to feed can easily be demonstrated by 
the use of a faulty mosquito net ; being unable to find their way 
out again they can be collected in the morning. They are rarely 
seen during the day and never in bright sunlight. Imprisoned in 
test tubes, however, they will readily bite men or animals at any 
time of the day. Sitting once under a large mango tree in some 
thick bush at a place called Welldad, on the coast of British 
Guiana, about midday, large numbers appeared and bit one with 
great rapidity and severity. It is efficient as an intermediate 
host for the development of Filaria nocturna, but is inefficient 
for F. demarquati. It also acts as the intermediate host for the 
