RESEARCH IN BRITISH WESJ' AFRICA. '317 



griiss and low shrubs. After Wan-a, a few rocks Login to appear In the river, but 

 navigation is comparatively easy until Bussa is reached. Two days were spent 

 (Ml this part, and although the river bank was carefully examined, no biting flies 

 of any sort were seen, with the exception of a species of SimuHum at Otono, 

 where a halt was made for the night. The day was dull, however, and this may 

 to some extent account for the absence of insect life. At Bussa, the vegetation 

 on the bank is very dense, and there is also abundant grass. In and around a 

 banana plantation, close to the river, Glossina palpalis was caught, while nearer 

 the Resident's house, which is situated some distance from the river, G. tuchi- 

 iKiides was extremely abundant. Other blood-sucking tlies obtained here were : — 

 Stiiinoxys nigra, Bcmhsinella luteolaterulis and a large new species of Tabanas, 

 as yet undescribed. The Resident at Bussa, Mr. P. de Patron, informed me 

 that it is almost impossible to keep horses in this district, as they invariably die 

 a few months after their arrival. 



Southwards from Bussa, there are numerous rapids, and navigation is both 

 difficult and dangerovis. Immediately after passing the town of Malali, the 

 channel is obstructed by projecting rocks and there is a stretch of cascades and 

 whirlpools, which extend for about three miles to the town of Garafini ; there 

 G. tuchinoides was caught. 



After Garafini, there is a stretch of about 20 miles of smooth water ; the 

 banks are covered with low shrubs, backed by higher trees. No biting flies were 

 seen in this part, but the fact that the morning was dull and that some rain fell 

 about mid-day, may account for their absence. When passing the mouth of the 

 Kontagora River * we caught one G. tachinoides, and another specimen of 

 the same species, near the mouth of the River Oli. In this region are the rapids 

 of Patassi, which are " composed of two sets of cascades each twelve to fifteen 

 feet in height and separated by a straight reach of some two hundred and eighty m^ 



yards." Following this is a stretch of two and a half miles of comparatively II 



smooth water, after which are the Great Rapids of Wuru. " Here the river is ''™ 



formed of two branches with a rocky island between. The fall of forty feet 

 between the summit and the foot of the rapid is distributed over some 1300 yards 

 of river, giving a slope of at least 1 in 100, and a current of from fifteen to 

 eighteen miles an hour. In the rains, the granite boulders are completely sub- 

 merged under a seething flood, and even in the dry season the water is thrown 

 up by the projecting rocks in sheets of foam, and the roar of the rapid is heard 

 for long distances on either side."t Near these rapids G. tachinoides is 

 abundant. 



From Leaba to Bajibo, there are numerous rocks in the river, but though navi- 

 gation is difficult, it is not very dangerous in the rains. No biting flies were seen 

 on this stretch, but the day was again dull. Bajibo is the extreme limit to which 

 small stern-wheelers can ascend the Niger even in the wet season, and then only 

 with great risks. Between this town and Jebba, G. tachinoides simply swarms, 

 and as many as 25 or 30 invaded the canoe at one time. The banks of the river 



* It may be useful to note here that a specimen of G. palpalis was caught by Mr. P. de 

 Putron, the Resident at Bussa, at Kulfu on a branch of the Kontagora Eiver on 26. VI. 10. 

 t" The Geography and Geology of Northern Nigeria." 



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