io THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
town, and behind, the town, half-a-mile away, there is also another large swamp 
running along the centre of the island, probably the old course of a river. 
In the large swamps innumerable mosquitoes occurred. Government House is 
situated close to the native town, surrounded by old stone ruins, which afford suitable 
hiding-places for mosquitoes in the dry season ; there were many mosquitoes 
about. One European was staying in the Government House when we visited it, 
and in his room I found, in the middle of the day, innumerable specimens of A. funestus 
and its varieties resting on the walls. A well present in the compound was devoid of 
Anopheles larvae, though larvae of the Culex type were present in numbers. These 
mosquitoes must have either flown from the swamp at the back of the town, where I 
found larvae in amongst the grass, or must have been bred in the river ; here I 
failed to detect larvae ; small fish occurred in the crevices and bays of the bank. 
The native town is similar to Bathurst, trenches in the streets drain into the river, 
and in the wet season, in consequence, innumerable breeding-places for mosquitoes 
are formed. Water is obtained by the natives from the river, as there are no wells. 
McCarthy Island appears to me to be quite unsuitable to permit of preventative opera- 
tions against mosquitoes. One must rely on such means as segregation and personal 
precautions against these insects. This latter method of precaution was, 1 believe, 
very successful in the case of Mr. Barnois, who, in 1898, stayed at McCarthy 
Island for some time without taking malaria fever, a mosquito net being successfully 
used. 
A native Mandingo town, Baia, was visited, and the country round explored. This 
town was situated two miles away from the river. The country round was perfectly 
level, most of it being cultivated ; ground-nuts, cuscus, and a bean being the chief pro- 
ducts. Everywhere the ground was dried up within a radius of two miles ; there 
were no breeding-places for mosquitoes within this radius, except one very deep well, 
forty feet, which had been discarded ; in this well only the Culex type of larvae occurred. 
In the huts innumerable quantities of Anopheles funestus and its varieties occurred, 
which could be obtained at any time of the ciay off the walls. So completely was 
there an absence of water that, at the margin of a well from which water was con- 
stantly being drawn, bees, butterflies, and other insects were present in great numbers, 
drinking up the water spilt on the ground. At this time of the year the only breeding- 
places for mosquitoes are in the neighbourhood of the swamps two miles away. 
Lieut. Young informed me while out shooting that he came across a tub in some 
fields a short distance from the town in which mosquito larvae were present. I 
searched along the margin of these swamps, but I failed to obtain larvae here or in the 
pools dug out for cattle. 
