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CHAPTER III.
THE MOSQUITOES OP KARACHI.
The present survey was started about the 27th of August 1912 and includes
a period of nearly six months. The order of examination was—The Civil Lines
and Frere Town, Cantonment limits, Kiamari and Harbour, Manora, Baba and
Bhit islands; then all the portion to the north of Bunder Road and last of all
to the south of it. There were no rains during the period. The investigation
included the survey of all the Oulicid Fauna, but for purposes of this report,
that of Stegomyia Fasciata (S. F.) will be treated separately.
The method of investigation was to examine all possible collections of
water for larvæ and hatch them out in the Laboratory. A net of muslin was
always used and passed round the edges of a tank ; or the contents of a gharra
•were emptied through it, and the washing of the inverted net was followed as
a routine measure. For wells a similar net was let down by means of a rope.
Section 1.
Breeding places.—A detailed consideration of all the breeding places met
with during the survey, indicated that the vast
majority of them are artificial, and differ with the
class of people residing in the locality.
1. The Harbour and Kiamari—The railway occupies a good deal of
space on Kiamari and in connection with these there are a number of offices,
godowns and bulk-oil installations. There are no docks, but a long line of
wharves extends from one end to the other. The whole of the area is 1 1/4 square
miles. A village built on model lines by the Port Trust forms a small part
only of Kiamari.
(a) Of the permanent breeding places—there were masonry tanks for
garden and other purposes, stand-pipes and the drains from these ; and in
the village 4 cattle troughs and cess pits to every house, imperfectly covered
by wooden boards. There are no wells; excluding the cess pits and drains
there are not more than 125 of these. Along the line of wharves and in
harbour limits, the total number of permanent breeding places is 17,
excluding the big tanks in connection with the steam power-house.
Disused troughs, tinpots and holes in the machinery in the harbour were
all dry.
I.—S. Fasciata were found in none of these except in six wooden
tubs which are semi-permanent fixtures.
II.—Anophelines in three garden tanks and the water-logged areas
about them.
III.—Culex found only in cess pits and 2 cattle troughs.
(b) Of the temporary breeding places are the gharras, i. e. earthern
drinking water-pots, antiformicas and tubs.
I.—S. Fasciata were found in 30 per cent. of the houses in the
village.
2. Manora differs from the above. There are 7 wells about 12 feet deep
which contain brackish water ; 4 tanks of 30 feet diameter hold the telegraph
cables, and though cleaned every eight days, were still found to harbour larvae
of A. Rossi. The water-supply is limited, and is brought over from across the
harbour and stored in mosquito-proof cisterns. There are no garden tanks and
the cess pits were free from any kind of larvae :—
I.—S. Fasciata found only in gharras of four bungalows on the
south side while the servants' quarter on the north side showed them
as usual.
II.—Anophelines—in 3 wells and 4 telegraph tanks.
III.—Culex in few cess pits on the south side.
H 305—3