THE TSETSE PROBLEM IN NORTH MOSSURISE. 337 



to liave done the same, and — an important statement if true — it was stated tliat 

 replete tsetses were occasionally found where cane-rats (abundant in much of this 

 country and very largely diurnal) had been many together. 



Pigs were as universally incriminated as baboons, and here I obtained a quite 

 excellent instance myself. In the " Oblong " (east end) in cloudy weather we 

 walked right on to four bush-pigs sleeping. In their hasty rush they left the flies 

 behind, and these streamed after them in great numbers and with quite a hum. 

 We captured nearly twenty that through repletion could scarcely fly ; all but one 

 were brevipalpis, the exception being a pallidipes, and more than half were females. 

 Austen records both morsitans and brevipalpis as feeding freely on wild pigs and 

 quotes Dr. Hearsey's statement that G. morsitans was seen to settle literally in 

 hundreds on the carcase of a wart-hog, behind which animal I also took these flies. 



My indirect evidence of the value of such animals as pigs to the fly was also 

 interesting. In a mile-wide patch of primary forest east of the Sitatongas, in 

 which I saw much brevipalpis, both native information and a careful search for 

 spoor showed that it could have been feeding on nothing but pigs, baboons and 

 smaller fry. The same applies to a piece of high, dense, secondary forest on the 

 western foot of the hills, into ^^•hich according to the owner of a kraal on the spot 

 (confirmed by the usual search for spoor) no big game had entered for some months. 

 It also applied, I am certain, to much of the rubber forest area in which pigs and 

 little blue duikers — and these only — are abundant. In one place a length of about 

 300 yards for a very great width was continuously turned up by the pigs and looked 

 like a hoed plantation. It made me wonder whether one of the forest hogs 

 (Hylochaerus) may not occur in these forests. 



Finally, working for over a fortnight round my camp on the Buzi east of Spunga- 

 bera, in an area in which game is relatively abundant, I made a special point of 

 studying the daily spoor in relation to the distribution of G. brevipalpis. To sum 

 up the result, there was a considerable area that I am certain was not entered by 

 big game during my stay, or for some days before it. There was a smaller, inner 

 area, immediately round certain kraals, that had probably not been visited by such 

 animals for many weeks or months. In general the spoor showed much less move- 

 ment of the big game now than in the wet season, yet the fly was equally present 

 throughout, lurking in all the thickets to attack passing animals. 



The only " passing animal " that showed a similar ubiquity was the bush-pig, 

 and I was convinced from the evidence that the fly was living practically entirely 

 on bush-pigs at the time of my visit. Man was not being attacked. My friend 

 Mr. G. D. Otterson spent a few days with me here, and declared on leaving that 

 the evidence of the fly's independence of the bigger game in the matter of food 

 was a " complete eye-opener " to him. 



I conclude from these observations bhat any attempt in north-west Mossurise 

 to destroy the fly by starving it in its permanent haunts is doomed to failure if the 

 bush-pigs, and perhaps the baboons also, are not destroyed ; and the destruction 

 of the pigs in this type of country is not easy. 



Two species of lemur occur in the fly areas. The larger of these, Galago crassi- 

 caudatus, is abundant in most of the brevipalpis country and sleeps exposed (but 

 perhaps protected by its fur) in the daytime. Bats, including the largish fruit-bat, 



