290 GLOSSINA BREVIPALPIS [CH. 



time the fly remains sheltered under the leaves of bushes, or 

 in the grass, always near the ground, or low down on the 

 trunks of trees, not more than two or three feet from the 

 base. 



At Kaporo, near the north end of Lake Nyasa, Davey 

 found that they preferred to rest on trees surrounded by 

 creepers and undergrowth, and hidden away in crevices in the 

 bark or under the branches. While thus resting motionless 

 Sanderson states that the flies are very diflicult to discover 

 and their presence would be entirely unsuspected. 



About 4.0 p.m. when the fly is ready to feed, it emerges 

 from its hiding-place and settles on dried leaves, sticks or 

 dust on paths, apparently lying in wait for a meal. As the 

 wild animals on their way to the water in the evening often 

 stand for a time on emerging from the forest on to a path, the 

 flies would thus have an opportunity of feeding. According 

 to Davey, although G. brevipalpis as a rule seems ready to bite 

 human beings in the evening, it does not set to work with the 

 same rapidity and voracity as G. morsitans. 



Stuhlmann kept large numbers of the flies in captivity at 

 Amani, German East Africa, and found that they required a 

 meal of blood at least every six or seven days, and by feeding 

 them every fourth or fifth day, individual females were kept 

 alive for upwards of four months. 



Sanderson writes : " The flies bite through dark clothes, 

 but have never been seen to settle on white surfaces " and 

 Stuhlmann frequently noticed that when a light and a dark- 

 coloured mule were walking side by side, only the latter was 

 attacked. 



In Nyasaland, Davey found that^ wherever he met with this 

 fly game was abundant. Once during the wet season, having 

 shot two bush-pigs about sunset, on going up to them he found 

 several G. brevipalpis apparently trying to suck blood from 

 the carcases, although for some time previously he had been 

 unable to find any of the flies. 



Although in captivity approximately equal numbers of 

 males and females are obtained from pupae, there is an enor- 

 mous preponderance of males among the captured specimens. 



