174 JAS. J. SIMPSON — ENTOMOLOGICAL 



through Ronietta, Roruks, Yonnibanna, and Makump, thence across the Rokell 

 River, and thus taps the oil palm country in the north of the Ronietta district, 

 the Karene and Kaballa districts. At Makump is situated the large experi- 

 mental factory established by Lever Brothers for the extraction of oil from the 

 fruit. Consequently, this railway is destined to be one of the most important 

 trade routes of the Protectorate, and as such should be duly regarded as a means 

 for the spread of blood-sucking insects and of the dissemination of the diseases 

 transmitted by them. 



The following notes will serve to show what insects have so far been found and 

 the localities at which they were taken. 



At Ronietta, only Glossina palpalis was found, but between that station and 

 Yonnibanna this species was obtained at several places, in addition to G. fusca, 

 while the same is true of the road between Yonnibanna, Kumrabai and Mayosso 

 (see map). At Mayosso, G. palpalis was abundant on the Pampana or Taia 

 River and also in the houses in the town. Tabanus secedens was also obtained 

 there. At Makump, on the River Rokell, G. palpalis was a perfect scourge, and 

 in the thicker bush around G. fusca was common. In addition to these, Haema- 

 topota sp. n. and Stegomyia fasciata both occur in the native town, the latter in 

 considerable numbers. 



It must be pointed out that in this brief survey of the railway only a few of 

 the most important stations were examined, and consequently the enumeration of 

 the species given may by no means exhaust the various types which may occur 

 at other places. Further, it cannot be said that the list given for the places 

 examined are complete, as at other times of the year different species may occur. 

 The systematic examination of the blood-sucking insect fauna of the various 

 places on a railway ought not to be confined to the enumeration of the species 

 which occur at the various stations and the elimination of these from such 

 stations, but should be of a more searching character. 



The role played by trains in transferring insects from one locality to another 

 cannot be overlooked, so that the regions between stations are equally important 

 in this respect, and too much attention cannot be paid to the nature of the 

 clearings on the banks of streams and such-like, and to the drainage of borrow- 

 pits, for these last, unless properly looked after, are invariably foci for the 

 dissemination of mosquitos. It is well known that tsetse, Tabanidae, and 

 mosquitos are often carried long distances in trains and motor waggons, and may 

 thereby be introduced with disastrous results into areas where they were pre- 

 viously unknown. Only one example of this need be cited, namely, in Accra, 

 which was free from tsetse up to the time of the construction of the railway 

 through a fly-belt. Now these insects are by no means uncommon, and it only 

 remains to be seen whether they will permanently establish themselves there. 

 Whether they do so or not, their presence is even now a serious menace to the 

 existence of horses in that town. 



(5.) Daru Sub-District. 



This sub-district was traversed between 1st and 17th August with a view to an 

 enquiry into the conditions which obtained in the out-stations of the West 

 African Frontier Force with regard to blood-sucking insects. Two of these 



