KING INSTITUTE, GUINDY, FOR 1927–28           7

to the touch. Trees were almost completely absent and this assisted the surface
heating of water. Samples of larvæ and pupæ were collected from every possible
source in the locality and were bred out in a temporary laboratory.

TABLE VIII.—The number and species of anopheles bred out from larvæ.

TABLE IX.—The nature of the breeding place and the number and species of
anopheles bred out.

        Tables VIII and IX give the results classified first by the nearest village and
second by the nature of the breeding place. The numbers given in the table as
bred out are only a fraction of the number of larvæ and pupæ caught. The
pupæ bred out without difficulty, but of the larvæ caught, practically only the
large mature larvæ bred out, most of the others died, and despite this careful
attention and replenishment of water from each original source. So it is evident
that the larvæ were not in a healthy state when caught which was probably due to
the advancing hot season not suiting them Culicine larvæ and pupæ were
abundant everywhere.

        As regards the species of anopheles bred out it will be noted that A. rossi is
the only one that does not carry malaria; the four others are well-known effective
carriers. A listoni may be neglected since only two were bred out.

       A short description of the different breeding places mentioned in Table IX is
required—see map III of the second report.

       1.The River Maneru.—Above the Mopad dam it is a fairly big river and the
chief source of supply to the reservoir. The part with which we are concerned
is that below the dam. This is now no longer a true river except from October
to December in the rains, when it receives both local drainage from the streams
and the overflow from the Mopad reservoir for which it acts as drainage channel.
In the rest of the year it contains pools of varying size and here and there some
running water. In these pools there was an overgrowth of rank vegetation,
particularly of “jombo” grass which grows to a height of 8 to 10 feet. Anopheles
larvæ of all five sorts mentioned in the table were found in large numbers in
these pools, stephensi culicifacies and rossi seemed to be the commonest. The
presence of stephensi is noteworthy. Near Botlagudur water was found flowing—
this was where there was a dip in the ground which points to the existence of a
sub–soil flow. But the current was very sluggish, due both to the smallness of
the amount of water, and to the presence of rocks and jambo grass. Here
too anopheles larvæ were found.

      2. Local drainage streams.—There are numerous tiny little streams called
“vaghus” emptying themselves into the Maneru. These get a constant supply of
water all through the year by seepage and overflow from the irrigation canals
and paddy fields. Not only were larvæ found in these streams, but they were
found abundantly in many small pools into which these streams had spread. The
larvæ were mainly culicifacies, the other species were also found.