TSE-TSE FLIES 19 



Some sixteen species exist, which are entilrey 

 Ethiopian in their distribution ; for though one species 

 {tachinoides) is found in the south-west corner of Arabia, 

 that area is faunistically part of the Ethiopian region. 

 Tse-tse do not occur in Africa north of the Sahara nor 

 south of St. Lucia Bay in Zululand. It is remarkably 

 interesting, therefore, that fossil flies have been found 

 in Colorado referable to this group, ^ and it has been 

 suggested by Osborn that they were responsible at least 

 in part for the extinction of many of the large mammals 

 which abounded in Cainozoic times and by their 

 migrations came into contact with blood-sucking flies to 

 which, and their associated flagellates, they had not yet 

 become habituated. ^ 



The first Tse-tse which I wish to mention particularly 

 is Glossina morsitans, known to travellers in Africa as 

 "The Fly," or, collectively, as "Fly." According to 

 Austen ^ the exact origin of the name is uncertain ; it 

 is believed to be a corruption of " Nsi-Nsi," said to be 

 the name given to blood-sucking flies by natives of some 

 parts of Africa. A passage in the Old Testament * possibly 

 refers to Glossina, although it may also apply to other 

 flies with the same habits : " And it shall come to pass 

 in that day, that the Lord shall hiss for the fly that is in 

 the uttermost part of the rivers of Egypt, and they shall 

 come, and shall rest all of them in the desolate valleys, 

 and in the holes of the rocks, and upon all thorns, and 

 upon all bushes." 



The early African travellers of the middle of the nine- 

 teenth century were, naturally, much impressed by the 

 fly which was so well known to the natives for inflicting 

 a " poisonous bite " upon their cattle. 



* Cockerell, Proc. of the United States National Museum, vol. liv. 1918, 

 p. 308. 



* Letter from Professor Cockerell in Nature, 1919, June 5, vol. ciii. 

 p. 265. « Monograph on the Tse-tse Flies, 1908, p. 32. 



* Isaiah, chapter vii. verses 18, 19. 



