XVI 



BIONOMICS 



279 



been abandoned, and after a time, as the natural bush has 

 grown up, the flies have reappeared in places where the native 

 food-plantations formerly were." The same observer is also 

 of the opinion that the tsetse is not entirely dependent for its 

 existence upon the blood of wild mammals. In Nyasaland, 

 enormous numbers of tsetse occur in districts that are almost 

 destitute of game and at the north end of Lake Nyasa, before 

 the advent of rinderpest, there were many thousands of buffalo 

 but no morsitans. On the other hand, it is the opinion of 



Fig. 73. Path through thin deciduous bush between Yallol and Fula Fara- 

 feni, Bathurst, to shew a typical haunt of G. mnrsitans. (After Simpson.) 



many observers that when game and especially buffaloes are 

 abundant, the fly also appears m large numbers and that after 

 the epidemic of rinderpest, following which in many regions 

 there was very httle game and practically no buffaloes, the 

 fly disappeared. Amongst these conflicting statements it is 

 difficult to arrive at the truth, but certainly Sharpe's observa- 

 tion that the tsetse may occur in the absence of wild mammals 

 shews that any scheme of game destruction would be both rash 



