498 



OTHER BLCKJD-SUCKING FLIES 



Glossina palpalis (Fig. 236) is a large dark species with black- 

 ish brown abdomen and with gray thorax having indistinct brown 

 markings. This species is found over th(^ whole of West Africa, 

 from Uie Senegal River to Angola, antl east to the upper valley of 

 the Nile and the eastern shores of the central lakes (Fig. 231, \\\). 

 Its range is thus nearly coincident with that of Gambian sleeping 

 .sickness. This species, more than any other except possibly 

 G. tachinoides, which occurs around the southern border of the 

 Sahara Desert, is dependent on the presence of water. Its natu- 

 ral range is said seldom to exceed 30 j^ards from the edge of water, 

 and the distance that it will follow animals or man is not more 



Fio. 236. Glossina ptilpnlis, carrier of Ganihiun and Xijicrian .sleeping sick- 

 ness. X 4. (After Austen.) 



than a few hundred yards. ]\Iutldy, reedy .sloughs or swamps 

 are not fre(iuented by this fly, but rather sandy- or gravelly- 

 banked streams with abundant overhanging vegetation. In 

 the rainy season the flies extend their range to headwaters which 

 are dry during the remainder of the year and retreat again with 

 the drj'ing up of the water. Il is fc.ncd tliat this species may 

 sometime ])ridge the short gape bclwccii the headwaters of the 

 Congo and the Zambesi, and liceomc c.'^tabh.'^hed along tlie latter 

 river and its tributaries, carrying sleejjing sickness with it. 



This fly probably feeds naturall\- on a number of diffenMit 

 animals. Wild game, especially the Situtunga antelope, is 



