6o8 



THE ANIMAL PARASITES OF MAN 



three-quarters of an hour. The puparium stage lasts from thirty-two to thirty-five 

 days. The puparia occur in well-drained humus close to water, sheltered by trees 

 or bushes, in crevices in rocks, and between the exposed roots of trees, sometimes 



in sand. 



[Bruce has shown that only a very small percentage of flies fed experimentally 

 on infected animals ultimately become infective, and that the infectivity of this 

 small percentage depends upon a delayed infection of the salivary glands. 



[A variety, wellmani of Austen, is found in Angola, Gambia, the Katanga district 

 of the Congo Free State, the Matondwi Islands of Tanganyika, etc. 



Glossina morsitans, Westwood. 



[This species has been shown by Kinghorn and Yorke, and also by Bruce, to be 

 responsible for the transmission of Trypanosoma rhodesiense, the micro-organism 

 producing sleeping sickness in man in Rhodesia and Nyasaland and also in parts 

 of German and Portuguese East Africa. Fisher and Taute have demonstrated 



FlG. 420. The tsetse-fly (Glossina niorsilans, Westwood). 



experimentally that Trypanosoma gambiense the sleeping sickness parasite of other 

 parts of Africa may also be transmitted by this fly, and in addition it is known to 

 be capable of disseminating several species of trypanosomes pathogenic to animals. 

 Of these, T. brucei (= ? T. rhodesie?tse], the parasite of tsetse disease, first 

 incriminated by Bruce, is perhaps the most important. 



[It is the most widely spread of all tsetse-flies ; its range extends from Sene- 

 gambia in the north-west to Southern Kordofan and Southern Abyssinia in the 

 north-east, and then southwards to the Bechuanaland Protectorate, North-eastern 

 Transvaal and Zululand. The actual localities given by Austen are Gambia, French 

 Guinea, Gold Coast, Togoland, Dahomey, Northern Nigeria, Congo Free State, the 

 Bahr-el-Ghazal, the Uganda Protectorate, German East Africa, and Portuguese East 

 Africa. 



[This species is confined to " belts," often of very limited extent, and appears 

 to prefer regions where there is sufficient vegetation for moderate but not excessive 

 cover and a hot, moderately dry climate. It is not, nearly so dependent upon 



