174 SIR ALFRED SHARPE — NOTES ON THE 



existence of any species o£ tsetse-fly. At the time when rinderpest visited 

 Nyasaland, there was a noticeable decrease in the quantity of })ig game in 

 some of the districts where tsetse-fly exists, especially as regards buffalo, 

 but I have never noticed that this had any effect on the presence of Glossina. 

 In Nyasaland the common kind of tsetse is Glossina morsitans. In certain 

 areas /?/56'(X is found, but no palpalis. 



Within a fly-area, as already stated, the quantity of fly met with varies 

 at different times of the year, and I am inclined to think that the prevalence 

 of strong winds to some extent drives the insects away. I have not noticed 

 that any special soil, bush or herbage seems to attract them. So far as 

 7norsitans is concerned it is certain that water is no attraction to them ; 

 nor have I observed that the presence of fly is in any way associated with 

 sand. In Nyasaland, Glossina is never found in open grass country; it is 

 only found in bush, not necessarily dense forest, but country scattered with 

 trees which give shade. G. morsitans is seldom found above 3000 feet in 

 Nyasaland. 



While I hesitate to give a decided opinion on the question whether 

 morsitans is entirely dependent for its existence upon the blood of wild 

 mammals, a point which is perhaps better answered by scientific men, yet 

 I can say that out of innumerable tsetse which I have caught I have never 

 found one which had any trace of blood in the abdomen, with the exception 

 of flies caught in the act of feeding either upon myself, upon natives or 

 animals; and the impression which I have formed is that tsetse-fly are 

 no more actually dependent upon the blood of mammals for their existence 

 than are mosquitos. Unless I am right in this opinion, I am at a loss to 

 understand how the enormous numbers of tsetse-fly which are found in some 

 areas can exist, as in many of those areas game is either extremely scarce 

 or almost non-existent. In Nyasaland it is distinctly noticeable that many 

 of the fly-areas are almost destitute of game, whereas, on the other hand, 

 some parts of the country where game is most abundant, such as the valley 

 of the Rukuru River, are entirely free from tsetse ; and in this locality, as 

 in others, buffalo are fairly abundant. At the north end of Lake Nyasa, 

 before the advent of rinderpest, there were many thousands of buffalo, but 

 no morsitans. 



I am acquainted with villages which are situated inside fly-areas, and 

 wherever the natives build their villages in such localities, and clear ground 

 for their food-gardens, tsetse immediately disappear from the cleared ground, 

 I have often noticed that, when approaching these villages from the bush, 

 fly which are following the carriers, or are actually upon their persons biting 

 them, will gradually disappear after entering the cleared ground, and by the 

 time the village is reached, no fly can be seen. On the other hand, I have 

 known cases where villages have been abandoned, and after a time, as the 



