RESKARCH IN BRITISH WEST AFRICA. 337 



bush. At this part o£ the river G. t'acliinuidcs iire fairly abundant, but no G. 

 palpuUs were sceu ; this is due, no doubt, to the nature of the vegetation. Tlie 

 town of Derri is situated at the eoniiueiice of the Garara and the Niger. lu tlie 

 dry season it stands higli and dry, and is surrounded by marshes and pools left 

 by the falling river, but in the wet season it is an island on which water rises 

 to the floors of the houses. In every respect it resembles Mureji at the con- 

 iluence of the Kaduna and the Niger (PI. IX, fig. 2). The following mosquitos 

 were obtained during my stay at this town : — Cidcx iin'idiosiis, Myzomijiu fuacsta, 

 Mansonioides uaifonnis, Buiiksliiella latcolatcralis and Ladhwiu miiniitmjiaforinis. 



It might be well to summarise briefly a few of the outstanding results of 

 this trip : — 



(I.) The journey was made at the heigiit of the dry season — from Decem- 

 ber 17th to December 2.5th. 



(2.) The banks of the River Garara, wherever seen, were covered with dense 

 vegetation, and numerous kurimis occur everywhere in the vicinity of the river. 

 In such situations G. palpalis was almost invariably found. 



(3.) The only other species of tsetse seen were G. tackitwides and G. loiKjipalpis. 

 The former was found at Dagu, near Wada. Evua, and between Gcrinya and 

 Derri. In all these places the bush was open and removed some distance from 

 the river. G. loiujipalpis was caught at Evua, and between Wada and Edzu, in 

 both cases in open country and still further removed from water. 



(4.) No Tabanidae were seen during the trip. 



(5.) Mosquitos : Mansonioides uniformis was caught at both Mama and Derri; 

 while at the latter town Gulex invidiosus, Myzvmi/ia funcstu, Baiikslnella luieola- 

 tcralis and Ludknviu inimomijiaforniis were also obtained. 



(6.) Ticks were seen only at Mama. 



(7.) The whole region along the Garara has a bad reputation for horses, 

 so that none are kept in the vicinity of the river, every attempt having met with 

 failure. 



(8.) At towns more remote, such as Lapai and those situated on high ground, 

 (■.//., Gau, horses and cattle are kept with impunity. 



(i) Derri to Bagana. 



Having thus completed the examination of the Garara River, I decided to, 

 visit the Province of Bassa, as sleeping sickness had been reported from this 

 region, and little or nothing had been done from an entomological standpoint. 

 For this purpose, it was necessary to go to Bagana on the south bank of the 

 Benue River. The journey was made in three stages : (1) to Kotonkerifi on the 

 Niger, by canoe ; (2) Kotonkerifi to Umaisha, by road ; and (3) Umaisha to 

 Bagana, by canoe. 



The trip from Derri to Kotonkerifi occupies only about five hours, and is 

 accomplished in native dug-out canoes. The river bank is mostly overgrown by 

 dense shade-trees, but there are numerous sand-banks, which are partially covered 

 with long xerophilous grass. Only one tsetse was seen, apparently G. tuchinoides. 

 Numerous crocodiles were observed basking on the sand-banks. The native 

 town of Kotonkerifi is about three miles distant from the point of disembarking, 



