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NOTES ON THE TSETSE-FLIES OF MURI PROVINCE, 

 NORTHERN NIGERIA. 



By Dr. J. Pollard, W.A.M.S. 



(Map.) 



As a general rule, on the Benue River and its tributaries, at least between 

 Abinsi and Lau, the tsetses found are Glossina tachinoides and G. palpalis, the 

 latter occurring far less frequently. 



G. tachinoides is, in nearly all cases, associated either with the thick fringe of 

 bush at the river-side (" kurimi "), or, where this is absent, with Mimosa asperata ; 

 both conditions being frequently present. Indeed, Mimosa asperata is practically 

 an indication of the presence of G. tachinoides in the Province, as has been proved 

 either by catching the fly or by obtaining evidence as to the impossibility of 

 keeping horses or cattle in the neighbourhood. 



There are, however, several exceptions, one of the most remarkable being 

 Grassol on the Mtarraba River, where cattle and horses are kept all the year- 

 round, although the Mimosa is plentiful on a partially swamped island in the 

 river below the town. This marsh would be a typical tsetse-haunt in nine out of 

 ten places in the Province. 



At Ibi, the Provincial Headquarters, tachinoides and palpalis are found on the 

 river and in the swamp adjoining the river, and here Mimosa asperata is plentiful. 

 Ibi is built on a ridge, and there is a swamp at the back of the ridge, as Avell as 

 that in front which adjoins the Benue. Curiously enough, this back swamp 

 is practically free from the Mimosa, and tachinoides is rarely found here though 

 morsitans is common. 



The distribution of morsitans in the " hinterland " of the river extends as far 

 back as a stream near Wukari, which town is at present an island of fly-free land 

 in a sea of tsetse. Beyond Wukari to Donga, on the river of the same name, 

 morsitans is found. The flies usually attach themselves to any party that may be 

 crossing one of the small shady streams. Along this road morsitans is usually 

 associated with a Haematopota. 



This Glossina has a peculiar habit of flying behind the natives, close to and on 

 a level with their ankles. It frequently settles on the ground for a rest, and, 

 incidentall}', it is by no means easy to stalk with a net, being difficult to see, even 

 though the background is generally yellowish. When flying near the ground the 

 abdomen of the fly hangs down nearly vertically and the dorsal surfaces of the 

 wings, as seen from behind, look upwards and a little backwards. The fly makes 

 constant flanking and rear attacks on its victims. 



Sleeping sickness epidemics have undoubtedly taken place in the past. Abinsi 

 was decimated about 20 years ago, and I had great difficulty in persuading 

 the people of Wukari, who are of the same race — Jukun — as those at Abinsi, that 

 they ran no risk in their fly-free town from the presence of a few persons 

 suffering from sleeping sickness whom I had sent out of Ibi, in order that they 

 should be away from a palpalis area. The smaller villages along the Benue often 



Bull. Ent. Research, III, pt. 2 (1912). 



