72
The absence of N. stephensi from the north of the island is probably duo
to the imperfect means of communication between this part and the Port.
Road communication between the north and south of Bombay has never
been good and even at the present time although the facilities for vehicular
traffic have been greatly improved there is very little direct communication
by covered vehicles between the south of the City and the extreme north
of the island.
174. The larvœ of Mysorhynchus larbirostris occurs most commonly in
F., G. and E. Wards, but it has also been met with in the very centre of the City.
Myssorhynchus jamesi is mast often found in the west and north of the island
and Myzomyia listoni and Myzomiya culicifacies in the east and north, round
about Parel village. At one time M. listoni was fairly common in the
vicinity of the reservoir at Malabár Hill and Mazagaon, and Major W. Glen
Liston I. M. S., found it breeding in considerable numbers in streamlets caused
by leaks from the water works. But lately it seems to have disappeared and
at the present time N. stephensi and N. Jamesi may be met with in the
few breeding places of this kind which still exist.
Culex Larvæ
175. It is unnecessary to enter into a detailed description of the Culicine
mosquitoes of Bombay, but a few facts regarding the species most commonly
met with in the City are recorded below.
Culex fatigans is the most common species of mosquito in many parts
of Bombay. It is found in enormous numbers even in some of the most densely
populated areas ; and is usually most troublesome in the dry weather and
shortly after the close of the monsoon. The entrances of the storm-water drains
with their catch-pits form some of the most prolific breeding places for this
mosquito ; and during the dry season when a small quantity of water passes
into these drains by reason of the watering of the streets and roads enormous
numbers of larvæ may be found in a considerable proportion of these catch-
pits. G, fatigans breeds most readily in foul water. Myriads of larvæ may
often be found in stagnant pools of brackish water that occur on the
foreshore in the area between the high and low tide line ; and they are
especially numerous in such places if fæcal contamination is common there.
At Malabár Hill very large numbers used to breed in the septic tank of the
sewage installation until measures were taken to prevent them; and in the
septic tank at Mátunga Asylum they are still to be found in enormous numbers.
They are also met with in large numbers of unused wells, of which there are a
great number in the City, many of them being exceedingly foul, and they are
almost invariably present in minor collections of water such as occur in barrels,
tubs, tin-pots, disused garden tanks, especially if the water has remained
standing for a few days.
In the large open storm-water channels larvæ of G. fatigans are always to
be found in large numbers and they are commonly to be met with in the
smaller and fouler collections of water that occur in uneven ground in every
part of the City during and after the monsoon, Swarms of the adult mosquito,
bred out from the storm-water drains, haunt many of the houses in the City ;.
and when it is almost impossible to catch adult; anopheles during the dry
season, scores of adult G. fatigans may be found with ease. In almost every
instance where complaints are made of the prevalence of mosquitoes, inves-
tigation shows the presence of large numbers of this species and owing to
the unsufferable nuisance caused by them in many parts of the City there is a
very prevalent notion among people who have heard the bare statement that
"mosquitoes carry malaria," that drains, gutter-traps and storm-water catch-
pits are largely responsible for the existence of malaria in Bombay.
176. Stegomyia mosquitoes do not become very prevalent in Bombay until
about August or September, except in buildings well supplied with fire buckets,
where they are common all the year round. In dwelling houses also where plants
are kept growing in vessels of water, or where flower vases are not frequently
attended to, Stegomyia may be met with at all times of the year. Slegomyia
larvæ are cot uncommon in the antiformicas or small vessels of water used to