500 OTHER BLOOD-SUCKING FLIES 



altitude of over 5000 feet, but usually occurs at much lower 

 levels. It feeds on the blood of almost any large mammal which 

 comes its way. It was long supposed that the fly was especially 

 dependent on the Cape buffalo, Bubalis caffer, as it undoubtedly 

 was before this animal was almost exterminated by rinderpest, 

 but the fly is certainly able to exist in the absence of the buffalo, 

 though often in less numbers than when the abundant food supply 

 was at hand. Baboons are said to be relished by the fly in some 

 parts of Africa. 



Glossina morsitans, though most active in the morning and 

 late afternoon, sometimes bites at midday and even after dark, 

 especially on warm moonlight nights. The habit of following 

 moving objects is especially marked in this species, and some 

 observers state that flies have followed them several miles, fre- 

 quently alighting on the ground to rest, or on the person pursued, 

 often without attempting to bite. 



The reproduction and choice of breeding places of this species 

 have already been mentioned. 



Although G. palpalis is undoubtedly the normal transmitter 

 of Gambian sleeping sickness and G. morsitans of Rhodesian 

 sleeping sickness, they are not the only species which have been 

 found capable of transmitting these diseases, at least under labo- 

 ratory conditions. G. morsitans has been found to be able to 

 nurse Trypanosoma gambiense in some districts but not in others. 

 G. pallidipes, which resembles G. morsitans but is larger, and 

 confined to southeastern Africa, can be experimentally in- 

 fected also. 



G. tachinoides is suspected of carrying sleeping sickness in parts 

 of Nigeria and Togoland. This is one of the smallest species, 

 being about the size of a housefly. It has very distinct bands on 

 the abdomen, and is browner and darker than G. morsitans. 

 It is found around the southern edges of the Sahara Desert and 

 in southwestern Arabia. Its habitats are practically the same 

 as those of Gl palpalis but it is active on dull days and early in 

 the morning when the latter species is quiet. It frequently 

 bites after dark, also, and in some places is said to be more 

 troublesome than mosquitoes. 



Another species experimentally able to transmit human 

 trypanosomes, T. gambiense, is G. brevipalpis, of South Central 

 and East Africa. This is a large species found in abundant 



