320 JAS. J. SIMPSON — ENTOMOLOGICAL 



this subject extendiug over a long period, iuformed nie that of the horses hrooght 

 into Lokoja over 60 per cent, developed trypanosomiasis within a year, and of 

 these 50 per cent, died within the same period. The question naturally arises : 

 What is the carrier ? It must be remembered that these horses are very seldom 

 taken out of the station, and consequently must be infected within that area. 

 As has been mentioned, HipiJocentrum versicolor does occur, though in small 

 numbers, but the most prevalent horse-biting flies are Stomoxys nigra and S. 

 calcitruns, whereas Glossina submorsitans has never been seen in Lokoja. 



These facts apparently point to Stomoxys as the carrier, and since we have no 

 direct evidence, experiments should certainly be made to prove or disprove this 

 possibility. But, apart from this, the fact remains that at present two out of 

 every three horses brought into Lokoja are incapacitated for work within a year 

 of their arrival, and it is almost superfluous to emphasise the necessity of trying, 

 so far as possible, to reduce the chances of infection by instituting a segregation 

 camp and making the stables mosquito-proof. To this subject, as well as to the 

 question of launches as agents in the dissemination of mosquitos, I shall refer 

 later on. 



('-) OiFa to Zungeru- 



The greater part of this journey was made by railway, and as by this means it 

 is possible to examine only the chief towns " en route " I shall here content myself 

 with giving a few general notes and the records of blood-sucking insects so far 

 available. The town of Offa is situated on the boundary of Southern and 

 Northern Nigeria and is connected with Lagos in the south and Jebba in the 

 north by the Lagos Government Railway. The biting flies recorded from this 

 station are : — Myzoinyia funesta, M. costalis, Hippocentrum versicolor, Tubaiias 

 secedens, T. sabanyustus and Tabanus sp. nov. near kmgsleyi. The only ticks 

 recorded are Apouomnia exornatum and Amblyomma nuttalli, of which Dr. E. C. 

 Hiscock obtained specimens from a large monitor lizard (locally called an 

 iguana) captured near the European quarters. 



Northwards the next important town is Ilorin, and here the following insects 

 were obtained : — Myzomyia costalis, Myzorhynchus paladis, T richorliynciius 

 (Gididoinyia) nebulosus, Reedouiyia annitlata and Culex sp. indet. 



At Jebba the only blood-suckers seen were Myzomyia funestu, M. costalis, 

 Glossina palpulis and Tabanus taeniola. The town of Jebba is now connected 

 with Zungeru by what is knoAvn as the Northern Extension of the Lagos 

 Railway, but at the time of my visit this line was under construction. Through 

 the kindness of the Director I was, however, enabled to examine this area as far 

 as Charati, the terminus at that time, and the folloAving records were made during 

 several excursions by trolley. 



At Grana, on the left bank of the Niger, from which the photograph shown in 

 Plate VII, figure 2, was taken, G. palpulis was far from uncommon, and this 

 species occurs at several places before reaching Mokwa. The railway skirts for 

 a considerable distance a large expanse of water known as Lake Tatabu, which is 

 not surrounded by nujch dense shade, but everywhere high grass is predominant. 

 Throughout this whole region G. iackinoides is extremely abundant. 



