MALARIA EXPEDITION TO THE GAMBIA 
3 1 
small quantities. The specimens obtained were caught chiefly in the European 
compounds. At the Cape a few artificial breeding-places were found in compounds. 
It would appear then that A. funestus and its varieties are rural mosquitoes, and 
require rather special breeding-places, while A. costalis is essentially a town-bred 
mosquito, and capable of utilizing any small collections of water for breeding purposes. 
At Bathurst I obtained one single specimen of the genus Panoplites, which was caught 
in the prison (P. uniformis, Theobald). This species of mosquito was never found 
breeding around Bathurst, and these mosquitoes were only seen in the marshes at 
McCarthy Island and Baia. Here they occurred in considerable numbers, and 
attacked natives and whites crossing the marsh at all times of the day in a very vicious 
manner. The observation of Durham and others with regard to Stegomyia fasciata was 
fully confirmed at Bathurst ; these mosquitoes only bite during the day, more 
especially in the early part of the afternoon. None of this species were collected 
in mosquito nets during the night. As yet we have no method by which any 
approach to the exact estimation of the number of mosquitoes in a district can be 
ascertained, although a rough estimation may be got from the number and extent of 
the breeding-places ; also the presence of mosquitoes at times when no breeding- 
places can be found, can be demonstrated by the construction of artificial pools as 
described by the Members of the Royal Society's Malaria Commission. No reliance 
can be placed on the statements of the white man in Africa as to the presence, or 
absence, or number of mosquitoes in the district. Many men become immune to 
the bites of mosquitoes after a time, and on the other hand, one or two importune 
mosquitoes cause as much annoyance as many. With the object of obtaining some 
idea of the number of mosquitoes entering a house at night, I employed the 
mosquito net method, which was found so useful by the Members of the Liverpool 
Malaria Expedition to Nigeria, in detecting the presence of mosquitoes in the absence 
of breeding-places. The Hospital was selected as the site for the experiment, and a 
net free from holes was rigged up over a bed in one of the wards, in which one of 
the orderlies or native patients slept. The net, instead of being tucked under the 
mattress in the usual way, fell short of the bed clothes, a space of two to four inches 
being left between the edges of the bed and the bottom of the net. The net was 
put down every night before the sun went down. During the evening, mosquitoes 
obtaining entrance below after feeding would climb to the top of the net. These 
were collected about 6 a.m. in the morning by myself or an intelligent orderly who 
brought them to me. Mosquitoes failed to find exit in nets rigged up in this manner 
even when they have become quite lively. The result of the experiment, which is 
given in the following table, was carried on throughout the months of November, 
December, and part of January. Though this method is as yet very imperfect it 
might be useful and interesting to rig up a similar net in the wet season, and to 
compare the numbers caught at the time. During the time this experiment was 
