KING INSTITUTE, GUINDY, FOR 1927-28
39
not within their sphere of control, they could not do anything more by way of
clearing the edges, canalizing the stream, etc. But even the mere oiling which
was being done in an admittedly half-hearted way, bad greatly reduced the
mosquito breeding and comparatively few larvæ could be obtained after a pro-
longed search, where before (in April) I had obtained countless larvæ and pupæ.
From larvæ obtained were bred out A. subpictus, culicifacies, A. stephensi and
A. karwari. This last is an addition to our April list of the Anopheline fauna of
this place. It was noted in our first report that the presence of A. stepheisi was
an uncommon feature for a seepage stream like this, but even more remarkable is
its continued presence at this time when A. culicifacies has displaced it even from
the wells which are the natural habitants of A. stephensi.
(c) The Yarri gedda.—Now this was a running stream (see photo. No. 2)
whereas in April there were pools of stagnant water. For the most part it runs
just outside the municipal limits, and a section of it cuts through the railway
area. This was the most important A. culicifacies breeding place—the larvæ
being found in shoals in several pools along the edges and caught among the
masses of algæ in the stream. Its importance becomes even greater, when its
nearness to the densely populated areas of Dondaparti and Gnanapuram is taken
into account. Besides A. culicifacies, a few larvæ of A. stephensi were obtained.
from it at its junction with the drainage channel from Gollapalem, and A. fuli-
ginosus and A. pallidus near Gnanapuram,
(d) The Gangela gedda.—(not mentioned in our first report) is the principal
storm water drain for the greater portion of the Allipur ward. There were
several pools along its bed, particularly numerous in the portion included in the
Daba gardens and behind the parade ground where there was very brisk breeding
of A. culicifacies and A. vagus.
A. small drainage channel in the golf ground was also breeding A. culici-
facies and a few A. stephensi.
(e) Tanks, ponds, etc.—Of these a small pond in Gnanapuram was the only
really dangerous one, breeding A. culicifacies. Allipur main road, where, only
the innocuous A. subpictus was found breeding in April, were now breeding
A. culicifacies. Larvæ of A. culicifacies were also present in the countless little
pools in the Gymkhana grounds in Waltair.
Larvæ of A. subpictus were found freely in the big tank at Gnanapuram, in
the Ratla koneru (see photo. No. 3) not reduced and the Yakkalamma Tank.
They were sparsely present in the Nerala Koneru, where A. fuliginosus and
A. vagus were also breeding and were not found at all in the Dykes tank,
Yerakkalamma tank, Katakammavari tank and the Watch Greshu tank.
(f) The Vupputeru swamp.—The swampy area (see photo. No. 4) was very
much more extensive than in April. Spirogyra was more plentiful and more or
less covered the whole water sheet. Caught among the masses of algæ were an
enormous number of anopheline larvæ. As in April they were all A. subpictus,
and no malaria-carrying mosquito larvæ at all was encountered. Estimations
were made of the electrical conductivity, total chlorides and total solids present
in the water. The salt content was found to be much less than in April (only
about a third, or 400 parts per 100,000 but still too high to allow of the breeding
of the common malaria carrying mosquitoes (A. indlowi a salt water breeder and
carrier of malaria has not been described from these parts). This confirms our
conclusion that though a source of great mosquito nuisance the swamp is not of
much malarial importance. Some huts are situated actually on the border of the
arms of the swamp (see photo. No. 6).
7. Seeing that the general spleen rate in April was 9.2 per cent now it is
almost certainly more than 10 per cent and the town must be classed among areas
of moderate endomicity. The spleen and parasites rates are high (near the
25 per cent limit) in the outlying crowded villages of Kancharapalem, Dondaparti
and Gnanapuram which are near Yarri Gedda; besides, the economic condition
of the people here is not satisfactory, the majority of the houses are mud huts
with palmyra leaf roofing dark and insanitary.