M 127
83. As to the swampy ravine at the head of A2, the vegetation is dense, and in places there is a rusty coloured precipitate in the water. Larval surveys were done but few or no larvae were found and this at times when the Camp catch was high. This ravine does not seem to be the source of the A. jeyporiensis trouble.
84. During the period March, April, May, June, larval surveys were done in the fallow rice fields in the upper reaches of the Shing Mun beyond Ho Pui—the limit of the controlled area in this direction. Many of these were found dry, some were found flooded with no larvae, from a few small number of larvae A. jeyporiensis and A. hyrcanus were obtained. As A. hyrcanus was being captured in the Camp catches in fair numbers at that time, it did not appear as if the supply were coming from these sources.
85. The ground north of Wo Li Hop was also investigated. Nothing of importance was found until the rains set in, when a few wet grassy fields were met with. These were drained by ditching.
86. A watch was kept upon fallow fields along the banks of stream A. north of the Access Road. During the rains these were found flooded and from some of them larvae of A. jeyporiensis were collected. Drainage was done.
87. More fallow fields were found in the fork of A5 north of the Access Road, and to the west of these as far as the head of Ravine B. All were drained as well as the head of B, which was ascertained to be a fertile source of A. jeyporiensis at times.
88. Towards the end of the year attention was paid to the fallow rice fields on the banks of stream Ala. It will be seen from the map that there are several Chinese villages much nearer these breeding places than the Camp, and which one would expect would be more attractive to the mosquitoes on that account. The direction of the local prevailing wind may have a bearing on this matter.
89. The monthly A. jeyporiensis catches until July were insignificant in comparison with the corresponding catches in 1933, but in May four new lines were occupied on the spur overlooking the head of stream A3 and in September five more, thus extending the Camp in the direction of Ala.
90. Collections were made during seven mornings in November in these fallow fields and about 5000 larvae obtained. 53% of these were A. jeyporiensis, the remainder being mainly A. hyrcanus. This breeding ground is being kept under observation in order to determine what action should be taken regarding it.