CONTROL OF TSETSE FLIES 503 



However, five species of Hymenoptera and two of Diptera are 

 known to parasitize the pupae of tsetse flies. It is possible that 

 some of these insects could be successfully exploited. The 

 adults of G. morsitans are attacked, according to Lamborn, by 

 a species of dragon-fly, Orthetrum chrysostigma, 

 which persistently pursues them and diligently 

 searches the vicinity of men and animals for 

 them. Elimination of breeding places is the 

 only feasible method for exterminating tsetses 

 in their early stages. 



Constructive measures should follow the de- 

 structive ones, such measures, for instance, as FIQ 23g 

 the cultivation of unfavorable plants and en- case of 'oi 



couragement of natural enemies. Following are > rsita ns, showing 



j u c j-u j * iTux- hole of emer genco 



summarized briefly the methods of fighting of a small chalcid 



tsetses advised by Bagshawe: parasite. x4. (Af- 



ter Waterston.) 



(a) clearing of fly-infested brush, and its re- 



placement by citronella grass or other plants noxious, or at least 

 not favorable, to the flies; 



(b) filling up, straightening out and draining of pools and 

 water courses where possible; 



(c) destruction of main food animals, if found feasible and 

 possible. (The wholesale destruction of wild game is not ad- 

 vised by Bagshawe.) 



(d) encouragement and introduction of natural enemies, and 

 investigation of food habits of possible enemies among birds 

 and bats. The black drongo, Dicrurus ater, and the small bee 

 eater, Melittophagus meridionalis, are known to feed on the 

 adult flies. 



(e) collection and destruction of pupae or adult flies. This 

 can be facilitated by creating artificial sites for depositing lar- 

 vse to which the flies will be attracted. Natives in Sudan arc 

 said to use gourds filled with blood for capturing flies to be 

 turned loose to torture the stock of enemy tribes. Other traps 

 have been devised also, among which should be mentioned the 

 black bird-lime cloths already described as being used on the 

 Island of Principe. 



Some workers have advocated the wholesale destruction of 

 wild game animals in parts of Africa where deadly trypanosome 

 diseases occur, in the hope that in this way the natural reservoirs 



