[ ” ] 
vening though they were abundant in the day. Later on the jungle was 
isited on two other occasions and the numbers ot anopheles present had 
onsidera'bly diminished. There is evidence that a great seasonal variation 
n the number of anopheles present in this jungle occurs, as on an unknown 
late last year, Mr. Carey observed anopheles in great numbers in the jun e 
t about fhe 3rd mile on the Langat Load, and on a later occasion he, with 
Dr Watson, visited this jungle, and they were unable to find a single 
mopheles I am at present unable to ofter any explanation ot the abo\e 
acts. The disappearance of the mosquitoes does not seem to have any 
■elation to the rainfall, nor should 1 expect this, as the swamps at the foot 
>f these hills where larvae were found are permanent, and therefore the 
weeding places would not dry up during the dry season. More extended 
observation mav give the clue at present lacking. It is to be noted that 
inecies of what'are probablv the more dangerous genera of Anophehna, 
mch as Nyssorhyncus Willmori and Nivipes, only breed in such swamps 
as are fed by springs or streams and not in the more stagnant swamps 
or artificial collections of water. Cellia (Anopheles) kochu may prove 
an exception to this rule. 
Jugra .—Two days only were spent here. 
The town is situated at the base of a solitary hill of about 1,000 feet 
high and on the Langat River. This hill rises like a solitary cone from the 
surrounding mangrove swamp which surrounds its base on all sides, 
the north and west the river Langat winds through this flat land to its 
mouth. The mangrove swamp is under tidal influence. 
The hill which is apparently composed in part of granite was originally 
entirely clad with jungle, but small areas have been cleared and are now clad 
with lalang. The jungle is for the most part composed of lar 0 e tiees, but 
on one side of the hill there are a few clumps of bamboos. V he undei- 
2round water is high and numerous springs keep the ground wet and 
marshv In the jungle there are one or two hillside streams running over 
a'rocky bed and merging here and there into silent pools and at the foot of 
the hill spreading out and forming swampy areas of considerable extent. 
Soil .—In the mangrove swamps the soil consists of a subsoil of clay 
covered with a layer of mud consisting of organic debris. On the hill the 
soil is largely composed of decaying vegetable matter. 
Rainfall .—Rain had fallen in quantity two days before I reached Jugra r 
but none fell during my stay there. 
The following mosquitoes were caught 
(a.) In houses:— 
Culicina. 
Mansonia annulipes. 
Culex fatigans. 
(b.) In jungle :— 
Anophelina. 
Myzorhyncus barbriostris. 
Culicina. 
Mansonia annulipes. 
Aedina. 
Verallina Butleri. 
Zeugnomyia gracilis. 
