SLEEPING SICKNESS PROPHYLAXIS 203 



encampments and villages, and to keep the roads clear. 

 The sun's heat has a most detrimental effect on the 

 fly and prevents them breeding in such situations. 

 Further, as in the case of the mosquito, the natural 

 enemies of the fly are to be encouraged. These consist 

 of both the enemies of the adult fly and those of 

 the pupcT, and amongst them are described certain 

 birds, wasps, spiders, ants, and fungi. The collection 

 and destruction of the pup^e ha^'e also been advocated. 

 The drainage of pools in the vicinity of camps and 

 villages is of use. An ingenious method of trapping 

 the adult fly has been practised with success by 

 INIr. IVIaldonado in the Island of Principe. The 

 labourers wear on their backs a black cloth smeared 

 with an adhesive substance to which the flies are 

 attracted. As many as 133,778 flies were caught on 

 one estate in a period of eight months by these 

 ambulatory " catch-'em-alivo " labourers. 



The destruction of wild animals which the fly 

 may use for sucking blood, such as the crocodile, is 

 also advocated. 



Having disposed of the method of attack as 

 regards the breeding grounds of the fly, let us examine 

 what can be done against the adult insect. In this 

 connection a series of regulations have been adopted 

 as follows : — 



Protect the body as much as possible from un- 

 necessary exposure to the bite of the fly — 



{a) by wearing plenty of suitable clothing (white), 



and leggings, 

 (/;) by systematic use of nets. 



