THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
suitable for the development of mosquito larvae, which were present here 
in fair numbers, chiefly larvae of Anopheles costalis. This condition 
obtained, when I arrived in Bathurst, and lasted through the months of 
October and November, that is, until the level of the ground water had 
sunk below the bed of the drain. The streets in which these conditions 
occurred are Dobson Street, Hagan Street, Blucher Street, Hill Street, 
part of Lemon and Buckle Streets. 
(c) The other kind of drain occurring in Bathurst is that which has been 
described as a trench dug along the centre of the streets. These drains 
either communicate with the big drains or discharge directly into the 
swamps. It was pointed out that the depth of these drains vary, and 
that they often are converted into a series of pools by rubbish and sand 
either thrown into them or by natives walking across. I found these 
drains to be almost universally infested with mosquito larvae, which 
occurred in great quantities along their course, and were for the most 
part all of the genus Anophehs ; only very occasionally did I find the 
Culex type of larvae in any amount. The small fish, which have been 
mentioned as being so beneficial in keeping the larger-made drains free from 
mosquito larvae, though occurring also in many ot the grass-choked 
drains, are here at a disadvantage, the larvae being to a great extent pro- 
tected by the grass and sticks amongst which they can hide ; also pools cut off" 
from the main masses of water occur in which fish cannot gain entrance. 
These drains supply Bathurst with the majority of its 
mosquitoes during the months of September, October, and 
November. They occur in the following streets : Fitzgerald Street, 
the drain runs along the centre of this street from the corner of Kent Street 
to Box Bar, where it is supposed to empty itself by a channel running down 
Lovel Place, entering the main drain leading into a swamp. The uselessness 
of these stretches as a whole are well illustrated by this drain, where I found 
the outlet completely blocked up with sand and rubbish, so that water would 
of necessity flow over Lovel Street to get into the swamp, and small fish 
for this reason also could not possibly gain entrance. Further, the drain 
itself had been converted into a series of long pools by the natives walk- 
ing across, carrying with them sand, etc., and, lastly, the thick, rank grass 
growing in the bed ot the drain, together with its naturally small fall, 
tends to retain the water in it. This drain is bricked across by two or three 
low, brick arches at the street crossings. Underneath these arches the 
bed of the drain dips, so that water collects in considerable quantity, 
which I found contained many Anopheles larvae ; also, in the course of 
