HABITS OF GLOSSINA MORSITANS IN NYASALAND. 175 



natural bush has grown np, the flies have reappeared in places where the 

 native food-plantations formerly were. 



I have known many cases, especially in the country lying between Tan- 

 ganyika and Mweru, where native villnges situated in fly-areas have possessed 

 cattle, noticeably so in the case of the powerful chief Nsama. In these 

 instances the cattle were always kept either inside the village itself, or else 

 were only allowed to feed immediately outside, and were always herded by 

 boys io prevent their straying into the bush. Goats, however^ are found in 

 all villages in Nyasaland, whether in fly-areas or not, and it is certain 

 that the bite of morsitans may have little or no effect npon these animals. 

 On the other hand^ I have been informed by natives living in fly-areas 

 that if goats are brought by them from other districts where no tsetse-fly 

 exist, they frequently sicken and die. I cannot myself vouch for the 

 truth of this. 



Generally, it will be gathered from the foregoing remarks that my 

 opinion is that the presence or absence of big game has little or nothing to 

 do with the existence of fly. I know that this opinion does not coincide 

 with that of Mr. Selous, whose experience is, I think, principally confined 

 to Africa south of the Zambesi. I can only say, however, that my obser- 

 vations during the last six or eight years have been very carefully made, 

 that the conclusions I have given have been very carefully arrived at, 

 and that they are shared, I think, by many careful observers in Central 

 Africa. 



Statements are made from time to time by persons who may even have 

 spent some years in Tropical Africa — notably so in Nyasaland — that tsetse- 

 fly is " spreading.^' As already stated, I do not think that '^ fly-areas '^ alter 

 their limits to any appreciable extent. Those who make these statements 

 do so no doubt because they honestly believe them to be true, but I know 

 from personal experience that in many cases fly has existed in the supposed 

 new areas for the past twenty years. There are various causes for fly being 

 now more noticed : — More attention than formerly has been called to the 

 subject ; cattle are now kept by natives in districts where formerl}^ owing 

 to wars and raids, there were none ; large native settlements have altered 

 their locations (notably at Fort Johnston, at the south end of Lake Nyasa), 

 and as the old clearings grew^ up fly appeared. Increased transport by 

 ox-waggons has revealed the existence of fly also in places where it was 

 not noticed before. 



