THE TSETSE PROBLEM IN NORTH MOSSURISE. 339 



more restless under its attentions than the buffalo, the hartebeests especially keepini^ 

 «p their dance when tsetse are about them ; so that the fly can feed more easily 

 on the buffalo." Neave has already made a suggestion to this effect. 



I shall discuss this subject further under the next heading. Elephants were 

 stated by the natives to be attended by tsetses when the latter are numerous, and I 

 took a male brevipalpis waiting on a much used elephant path. Roubaud and 

 Bouet (referring to G. longipalpis) are both quoted as speaking of a special association 

 betw^een tsetses and the elephant and hippopotamus. 



Man —and the Fly's Preferences. 



Using cattle as I did, I obtained abundant and excellent evidence that G. morsitans 

 and G. pallidipes attack these animals more readily than they attack man, that 

 G. morsitans attacks man more readily than does G. pallidipes, and that the latter, 

 in turn, attacks man far more readily than does G. brevipalpis. It constantly and 

 everywhere happened that the carriers passed through a place without drawing 

 fly and that the cattle coming just afterwards attracted many, A dozen to twenty 

 carriers are more conspicuous than two or three head of cattle and their scent is 

 overpoweringly stronger. Similarly I have seen a fly {pallidipes) on a leaf beside 

 the path allow carriers to pass it unmolested and then at once fly out to my donkey. 

 Another piece of evidence was afforded by a fly {brevipalpis) that I found perched 

 on a projecting slab of shale in the path, facing away from me. I stopped short 

 (about two yards away) and had the cattle (immediately behind me) turned into 

 the grass. After about two minutes the fly flew back to me and, without alighting, 

 returned to its perch. I then had the two cattle immediately brought up, the 

 leading ox standing nearly level with me in the path. The fly shortly flew back 

 again, first to myself, then, swerving off, to the ox, under which it at once settled 

 and began to feed. 



A point that struck me in the morsitans area was that whereas when we were 

 digging for puparia there was often delay before a fly attacked us (one fly was actually 

 seen watching on a tree-trunk for a time before it came), the cattle were attacked 

 quickly. 



Man is attacked by all these flies much more frequently in the rainy season, but 

 the increased attacks are probably not more than proportionate to the great increase 

 in the number of the flies at that time of year. Dr. Lawrence has sent me records 

 of occasional attacks on natives at his homestead at Gogoyo's even by brevipalpis, 

 and as for morsitans (no doubt in company with pallidipes), I was informed by the 

 natives across the Sita tongas that they become at times unbearable, forcing every 

 man to carry a leafy twig with which he continuously switches his back and shoulders. 

 G. pallidipes (it is stated) also becomes a nuisance in places west of these hiUs. 



Concerning the practical question, " if other sources of food were eliminated, 

 could the tsetse still keep going with the aid of man 1 " it is certain from the 

 observations of Lloyd, Maugham, Stephenson-Hamilton, myself and others that 

 the tsetses would then attack man much more. Tsetses (as I have seen) constantly 

 obtain full feeds from man and escape unscathed and, where the bush comes up 

 to a village, so far from avoiding it, morsitans and pallidipes — ^but not brevipalpis — - 

 appear to become rather a nuisance. 



