TRYPANOSOMIASIS IN THE ABSENCE OF TSETSES. 235 



While in the Lumbwa and Kisii Reserves I was collecting blood-sucking flies 

 at various lower points on the same river system, as far as a point on the Sondo 

 River about fifteen miles in a direct line from the farm, and with the exception of a 

 Simulium, to be referred to shortly, the only specimen taken of a fly of any 

 additional genus was a single individual of Tabanus taeniola, P. de B., var. variatus, 

 Walk., captured in the Lumbwa Reserve about ten miles due west of the farm. 

 While it is not impossible that that fly might be taken on the farm, it can hardly 

 be common there. The Lumbwa herd-boys on the farm told me that my captures 

 included specimens of all the blood-sucking flies which they knew to be there. 



The cattle on the farm were not dipped and some ticks were collected from them. 



The species of bloocLsucking flies and ticks taken were the following : — 



Hacmatopota similis, Ric. — 10 $?. 



hirta, Ric— 2 ? ?. 



brunnescens, Ric. — 11 ?$. 



alluaiidi. Sure. — 5 ? $. 



ugandae, Ric. — 28 ?$. 

 Stomoxys calcitrans, L. — 15 (^cJ, 22 $?. 

 varipes, Bezzi — 3 $$. 

 nigra, Macq. — 1 $. 

 Amblyomma variegatum, F. 

 Boophilus sp. 



Mr. Orchardson told me of an extensive area of thick thorn forest in the Chemosit 

 River district of the Lumbwa Reserve which the Lumbwa leave almost uninhabited 

 owing to its being infested with a fly which proved to be a Simulium. The belief of 

 the Lumbwa, about which he told me, that the bites of this fly cause a disease of 

 human beings will be discussed directly. He further suspected that this fly might 

 be the carrier of some disease of cattle. In 1917 he and a neighbour carted maize 

 to their farms near Kericho from Litun, and outspanned their oxen just off the Sotik 

 Road near to the Chemosit and Jamji Rivers. Afterwards some of the oxen used 

 in this work died, each planter losing about half a dozen animals. " These," he 

 said, " gradually faded away and died." Some were ill for weeks, some for months. 

 They were not seen by any veterinary officer. Now there is a considerable area 

 of thorn forest on and near the farm where the outbreak of trypanosomiasis had 

 occurred, so this was a suggestion to be followed up. 

 My inquiry, however, yielded negative results, for : — 

 {a) Those Lumbwa who live in the infested area keep cattle. One young man 



had come two years ago from a district clear of Simulium in order to 



graze his father's cattle in the infested country, for much of the grazing 



is good. 

 [h) The people told me that Simulium bites cattle, sheep and goats, but they 



said that it does not give the animals any chsease. 



(c) It was pointed out to me by Mr. C. M. Dobbs, the District Commissioner 



at Kericho, that cattle are frequently outspanned just off the Sotik Road 

 in the same place as those of Mr. Orchardson and his neighbour, but he 

 had not heard of any other cases of disease supposed to have been 

 contracted there like that of which Mr. Orchardson had spoken. 



(d) I failed to find Simulium so far east as the Sotik Road, the nearest point 



where a specimen was captured, and that at a place where Simulium 



was not numerous, being a mile and a half to the west, though it is not 



impossible that the fly may occur on the road in small numbers. 



After this visit to the Reserves I returned to the farm of the outbreak and again 



collected blood-sucking flies there and in the thick thorn forest on adjacent land, 



