93 



fly's independence of the bigger game in the matter of food was a 

 ' complete eye-opener ' to him. 



" I conclude from these observations that 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." 



For various reasons Swynnerton is not apparently inclined to attach 

 great importance to lemurs, certain bats, and various small, " largely 

 diurnal " rodents and insect! vores. He thinks that " the part played 

 by the small nocturnal mammals, including bats, needs far fuller 

 testing than it has received," but adds that : " Dassies or rock- 

 rabbits (Procavia) may be of much use to the fly, but very locally and 

 only in rocky places." 1 



In certain localities not only bush-pigs, but domesticated pigs play 

 an important part in the sustenance of Tsetse-flies. Thus, according 

 to Greggio (56), in the Inkissi Valley, Central Belgian Congo, while 

 there is no direct correlation between the existence of the human 

 trypanosome and that of the pig, indirectly the keeping of pigs con- 

 stitutes a serious danger to the inhabitants, the animals affording an 

 abundant and favourite food-supply for Glossina and encouraging its 

 increase. The pigs roam freely about the country in search of food, 

 which is often to be found in the most fly-infested spots, and return to 

 the villages bearing flies on their bodies. These include several species, 

 G. palpalis being the most common. In a subsequent paper (58) the 

 same author states that white pigs are extremely rare in the Inkissi 

 Valley, but are attacked by Glossina to the same extent as are black 

 or brown animals. Though the fly certainly prefers a dark colour, 

 when a herd is composed entirely of white individuals it attacks them 

 readily. Animals kept in the villages, which never go down to the 

 river, are equally affected, because other pigs that are running free 

 bring back palpalis to the village, and animals tied up close to the huts 

 are much worried by the flies. 



Again, in the Kwilu district, Western Belgian Congo, according to 

 Schwetz (132), G. palpalis is established permanently in small isolated 

 thickets near or actually in villages on hills, and sometimes at a con- 

 siderable distance from any water, and the presence of pigs in the 

 thickets referred to is said to be the reason for this strange phenomenon. 

 Christy (29), while attaching special importance from our present point 

 of view to the bush-pig and wart-hog, considers the semi-domesticated 

 pigs frequently seen in native villages to be even more, dangerous. 

 Lastly it may be noted that, in the remarkably successful measures 

 adopted some few years ago for the ridding of the Island of Principe 

 from G. palpalis and sleeping sickness, the destruction of the wild 

 (feral) pigs, which swarmed in the island, occupied a prominent place 

 (see p. 142). 



The extent to which Tsetse-flies feed upon the smaller animals 

 mammals, birds and reptiles is a matter of great importance, and all 

 observations upon this subject that can be collected will be extremely 

 useful. This brings us to one of the most hotly debated questions, 

 namely, that of big game. 



1 Lloyd (91) states that in three instances in Northern Rhodesia, in which 

 G. morsitans was feeding on rabbits, the flies were observed to be distended 

 with a clear fluid instead of blood ; this may have been serous fluid, obtained 

 by piercing the body wall. 



