M 139
On the 18th of November a hill stream crossing the Tytam bridle path was searched carefully for two hours; no larvae were got but one pupa obtained hatched out as A. maculatus. The nearest habitation was half a mile distant on one side, and three quarters of a mile distant on the other side of the stream. There were two police stations with four or five police in each.
The larvae of A. maculatus are usually abundant in hill streams in populous areas. Should it prove to be the case that they are absent or few in numbers in such streams remote from human habitations, there must be some attraction in connection with these habitations. Few adults are captured in dwellings in day and night catches in comparison with the larval population, so it would not appear to be the human element.
The larvae have been found in numbers in localities where neither horses, cattle nor pigs were kept, so these animals do not seem to be the draw. The adults do not appear to feed on frogs or birds. It, however, is possible that dogs may prove one of the attractions.
It is hoped in the future to make further investigations into the matter by ascertaining if they can be caught at night coming into stables or byres, or caught in the open, in order to obtain sufficient material for precipitin tests and dissections.
A. minimus. Larvae of A. minimus were met with in their usual breeding places in the flat portions of streams amongst or near the hills and in irrigation ditches. In October, they were found in terraced rice fields containing rice almost fully grown. It was reported that the water was being drained from these rice fields. In the streams, except for an occasional specimen, they were not found in pools devoid of vegetation or algae; hence clearing of streams alone is likely to have a good effect by increasing the velocity of the current and discouraging the growth of vegetation and algae. In one instance, four A. minimus and one A. maculatus were found in water below a dead pig in an advanced stage of decomposition. More work is required to ascertain if pockets in hillside clefts and pools in the steep portions of hill streams harbour these larvae to any extent, also if they can be found in numbers in streams remote from the hillfoot and outside tidal influence, as results affecting the extent of anti-malarial operations are likely to be obtained. Fewer adults are caught in the colder months, as will be seen on reference to Tables IX and X for the Wong Chok Hang catches. Similar results were obtained in this locality in 1932. No anti-malarial operations except catching have been done there. As in 1932, this Anopheline was found to be an important carrier of malaria and harboured larval filaria.
A. hyrcanus. Larvae of A. hyrcanus var. sinensis were found in rice fields at various stages of the crop. At times, they were best demonstrated by muddying the water. They were met with
M 139
On the 18th of November a hill stream crossing the Tytam bridle path was searched carefully for two hours; no larvae were got but one pupa obtained hatched out as A. maculatus. The nearest habitation was half a mile distant on one side, and three quarters of a mile distant on the other side of the stream. were two police stations with four or five police in each.
These
The larvae of A. maculatus are usually abundant in hill streams in populous areas. Should it prove to be the case that they are absent or few in numbers in such streams remote from human habitations there must be some attraction in connection with these habitations. Few adults are captured in dwellings in day and night catches in comparison with the larval population, so it would not appear to be the human element.
The larvae have been found in numbers in localities where neither horses, cattle nor pigs were kept, so these animals do not seem to be the draw. The adults do not appear to feed on frogs or birds. It however is possible that dogs may prove one of the attractions.
It is hoped in the future to make further investigations into the matter by ascertaining if they can be caught at night coming into stables or byres, or caught in the open, in order to obtain sufficient material for precipitin tests and dissections.
A. minimus. Larvae of A. minimus were met with in their usual breeding places in the flat portions of streams amongst or near the hills and in irrigation ditches. In October they were found in terraced rice fields containing rice almost fully grown. It was reported that the water was being drained from these rice fields. In the streams, except for an occasional specimen, they were not found in pools devoid of vegetation or algae, hence clear- ing of streams alone is likely to have a good effect by increasing the velocity of the current and discouraging the growth of vegeta- tion and algae. In one instance four A. minimus and one A. maculatus were found in water below a dead pig in an advanced stage of decomposition. More work is required to ascertain if pockets in hill side clefts and pools in the steep portions of hill streams harbour these larvae to any extent, also if they can be found in numbers in streams remote from the hillfoot and outside tidal influence, as results affecting the extent of anti-malarial operations are likely to be obtained. Fewer adults are caught in the colder months as will be seen on reference, to Tables IX and X for the Wong Chok Hang catches. Similar results were ob- tained in this locality in 1932. No anti-malarial operations except catching have been done there. As in 1932 this Anophe- line was found to be an important carrier of malaria and harboured larval filaria.
A. hyrcanus. Larvae of A. hyrcanus var. sinensis were found in rice fields at various stages of the crop. At times they were best demonstrated by muddying the water. They were met with
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