THE TSETSE TROBLEM IN NORTH MOSSURISE. 343 



X. — Effect of the Rinderpest. 



The efiect of the rinderpest is of practical importance in relation to the question 

 of destroying the game to starve the flv. 



In reply to my question, addressed to many natives, as to whether the fly became 

 less after the rinderpest, I received two answers, one from south of the Lusitu, 

 the other from north. It may be stated at once that both buffalo and fly are said 

 to be much more abundant, and to have been so before the rinderpest, in the Brachy- 

 stegia area north of the Lusitu than in that to its south (both of them on the gneiss 

 and carrying both nwrsitans and pallidipes), so that the difference in the replies 

 may perhaps be genuine. 



The reply from the former area (from the countries of Muchamba, Usambai and 

 Udombe) was that the rinderpest was followed for two seasons only by a definite 

 reduction in the numbers of the fly. In the second of these seasons it was already 

 more numerous, in the third season and subsequently it was as numerous as ever. 

 The bui^alos were still scarce, so that if this statement is correct and there were 

 also any real connection between the rinderpest and the fly's reduction, one 

 explanation might be that the fly had previously become specially dependent on the 

 buffalo, owing to the latter's immense relative numbers, and took a season or two 

 to adapt itself completely to the habits of the other larger mammals. Wart-hogs 

 and baboons were stated to have been particularly abundant. Another explanation 

 \vill be suggested below. 



The answer I received from south of the Lusitu, in the fly-areas both east and 

 west of the Sitatonga Hills, was that the rinderpest was followed by no noticeable 

 reduction of the fly at all. One man stated on the contrary that they then bothered 

 the natives terribly. Another made the quite sound suggestion that perhaps with 

 their other food destroyed they attacked men more, so that, though fewer, they 

 seemed as many as ever. All insisted that, though certain abundant species of 

 game were killed off, plenty of other food remained, in the form of bush-pigs, wart- 

 hogs, baboons and part of the larger game. 



To the above evidence I am able to add a little of my own. In 1900 I passed 

 with carriers through a portion of the morsitans fly-area. Hunting on 31st May 

 and 1st June in and near the large wood and series of adjoining vleis called the 

 " Mahloka " or " Masando " near the Umvuazi we were beset by very great numbers 

 of tsetses, which also kept with us for considerable distances — ^far heavier attacks 

 and " followings " than any I experienced in 1918. At that time buffalos were 

 still exceedingly rare as the result of the rinderpest of four years before. I saw 

 no trace whatever of them during that trip — a> shooting trip — and local natives 

 I have consulted have confirmed the fact of their absence. I have already mentioned 

 tiie loss of a beast beyond the limits of the present fly in 1900, and the capture 

 in the same year of a tsetse south of Spungabera, just inside the edge of the present 

 permanent fly. 



On the other hand, my information from north of the Lusitu, if reliable (it was 

 given to the members of my native expedition thither, not to myself), certainly 

 seems to suggest that in some fly-areas an effect may have been produced. The 

 real, dense, busily breeding centres of a morsitans belt may in the dry season at 



