RESEARCH IN SIERRA LEONE. 173 



and all of these invade the various officers' quarters and the mess. Mosquitos 

 were very troublesome during my visit, and along with Dr. Powell I made a 

 survey of the various parts where larvae might be expected. In the house 

 kindly put at my disposal by the Officer Commanding during my stay in Daru, 

 nearly all the species of mosquitos mentioned above were obtained, and this may 

 be taken as typical of all the European quarters. 



Larvae were found in various water-filled depressions in the soil, in hollows in 

 trees, in the receptacle formed by the bases of the leaves of pineapples, in canoes 

 at the river-side, in pools in the concrete floor of the verandahs of unoccupied 

 houses, and in the bamboo fencing around the gardens kept by the native 

 soldiers. The last-named of these was the most important. Bamboos were used 

 for fencing purposes and no attention was paid to where these were cut ; so that 

 in nearly every pole several inches of the terminal internode formed a receptacle 

 for water. In every one of these examined, larvae were found, and in almost 

 every case S. fasciata and S. apicoargentea were bred out. Three remedies for 

 this unfortunate and dangerous state of affairs suggest themselves : — (1) to dis- 

 continue the use of bamboo for fencing purposes ; (2) if bamboo must be used, 

 to see that all the tops are carefully trimmed off immediately above the node ; 

 or, (3) to split the bamboo for some distance from the top. 



The third of these is not very satisfactory, but it was the method adopted with 

 the existing fences at Daru owing to its being impossible to uproot all the 

 fencing at that time. It can be looked upon, however, as only a temporary 

 measure, but Col. Newstead, when this state of affairs was pointed out, to him, 

 very willingly agreed to discontinue the use of bamboos for fencing at the 

 earliest opportunity. 



Of equally great importance and of a more permanent character is the 

 question of extensive clearing around the cantonments. Dense bush extends 

 from the railway line to the fencing around the various officers' compounds on 

 the one side, and from the river bank to the compounds on the other. There can 

 be no question that this whole area should be absolutely denuded of all vegeta- 

 tion, as the ground, being very uneven, contains many water pools in the wet 

 season, and is a favourite dumping ground for all sorts of tins and rubbish by 

 careless servants. 



As pointed out to me both by the Medical Officer and the Officer Commanding 

 the Battalion, the sanitary gang, as at present constituted, is totally inadequate 

 for undertaking new work such as this ; in fact, it has more than enough to do 

 to keep the station as it exists at present in anything like a sanitary condition. 

 Certainly some special effort should be made on the part of the sanitary 

 authorities to establish and maintain in the first instance such a clearing as that 

 mentioned, in order to abolish, so far as possible, the scourge of mosquitos and 

 other blood-sucking insects from a station where so many white officials are 

 constantly resident and in close contact with native troops. 



At Baiima, a few miles further up the railway, Glossina palpalis, G.fusca and 

 Tabanus besti var. arbucklei were found, while at Pendembu G. palpalis and a 

 new species of Tabanus were the only blood-sucking insects seen. 



As has been said, a branch line runs in a north-easterly direction from Boia 

 Junction, 64 miles from Freetown, to Makump on the Rokell River. It passes 



