RESEARCH IN BRITISH WEST AFRICA. 319 
eastern half of the Protectorate. It is also an important political centre, 
and all officers stationed on the Chad and Benue systems must pass through 
Lokoja going to and from their stations. Here also is situated one of the three 
large European hospitals of the Protectorate, under the charge of a Senior 
Medical Officer. Further, it is the headquarters of the 2nd Battalion of the 
West African Frontier Force. All these combined together ensure a large 
permanent European population as well as a continual ingress and egress of 
officials and others passing north and south. 
The town stands on the right bank of the Niger, at the base of a large 
flat-topped hill, Mount Patti, which is covered with moderately thick bush. On 
the left bank is a large, flat, alluvial plain formed by the confluence of the two 
rivers. Close to the river are several trading factories, the Marine Head- 
quarters, and the stores of the Public Works Department, and, owing to the 
nature of the bank and the varying level of the river, pools of stagnant water 
are far from infrequent, in many of which mosquito larvae were found. 
Mosquitos are very troublesome all over this part, and swarms of them come 
from the banks and invade the steamers lying alongside. In four buildings 
occupied by Europeans, as well as on a launch tied up to the bank, I found 
Stegomyia fasciata and Myzomyia costalis. The majority of the European 
houses are on much higher ground, and at some distance from the river ; but in 
the Post Office, some five hundred yards from the river bank, S. fasciata was 
seen. Throughout the town, the most prevalent mosquito was M. costalis. 
Glossina palpalis has been recorded from Lokoja, but although I visited this 
town on two different occasions, first in August, during the rains, and afterwards 
in January, in the dry season, I saw none, and from the nature of the clearings 
so efficiently carried out by the political and medical officers, I do not think that 
this species actually breeds within the limits of the settlement, but it may 
occasionally follow natives or others from the bush on Mount Patti. During my 
second visit, Dr. E, A. Chartres, the Senior Medical Officer, was clearing a 
small banana grove which existed in a low-lying, damp situation, but careful 
search failed to reveal either the insects or pupal cases. In June, 1911, 
Dr. Chartres caught a specimen of G. tachinoides near his house, and in 
August of the same year one G, palpalis inside a ward of the European Hospital. 
Ticks are said to be very troublesome at certain seasons of the year ; both 
Amblyomma variegatum and Lhipicephalus sanguineus have been recorded from 
the district. Culicoides sp., and Simulium sp. are abundant. Myzomyia costalis, 
as has been mentioned, is the most prevalent mosquito, but apart from this 
species and Stegomyia fasciata near the river, the only others seen during my 
visit were Mansonioides uniformis, Mucidus mucidus and Nyssorhynchus pharo- 
ensts. Dr. Chartres has, however, collected the following species since that 
time :— Culex decens, C. grahami, C. guiarti, C. invidiosus and Myzomyia umbrosa. 
Hippocentrum versicolor has been recorded from Lokoja, but is far from common, 
while in and near the stables Stomoxys nigra, S. caleitrans and Hippobosca 
maculata simply swarm in hundreds. 
The number of horses in Lokoja is necessarily large, and the rate of mortality 
is excessively high. Capt. Manuk, late I.M.S., who has made a special study of 
