CRAB-HOLES, TREES, AND OTHER MOSQUITO SOURCES IN LAGOS. 269 



The following species obtained in this locality on other occasions may be added 

 to the above lists, viz.: — Hodgesia sanguinis, Theo., 0. ochraceus, Theo., C. univittatus, 

 Theo., Mansonioides unifonnis, Theo., Taeniorhynchus metallicus, Theo., Urano- 

 taenia balfouri, Theo. , U. bilineata, Theo. , var. fraseri, Theo. The last-named was 

 at one period fairly abundant in the neighbourhood of Government House, but the 

 others are of rare occurrence. 



On 31st August 1915, a strong tornado from N.E. occurred about 6 p.m., in the 

 course of which very numerous mosquitos were blown into the quarters occupied 

 by the Medical Officer of Health. An examination of 36 specimens captured for 

 identification gave the following curious result : — Culex decens, 33 $, 1 (J ; Culex 

 rima, 1 J ; ilf . africanus, 1 $. 



There is here a lack of correspondence with the record of mosquitos taken in the 

 same rooms during the immediately preceding 3 months, which is as foUows : — 

 403 mosquitos comprising A. costalis, 375 or 93 per cent.; 0. nigricephalus, 8 ; 

 C. nebulosa, 6 ; C. thalassius, 3 ; C. decens, 2 ; 0. irritans, 2 ; 0. do^nesticics, 2 ; 

 S. fasciata, 2 ; C. quasigelidus, 1 ; M. africanus, 1 ; T. 7netallicus, 1. 



It is probable that on this occasion some particular nidus close at hand wa& 

 stirred up. A search further off in the Ikoyi Plains to windward of the populated 

 area, where there are swamps and small surface pools, crab-holes, etc., as well as 

 a few out-lying hamlets, revealed chiefly A. costalis, 0. irritans, U. annulata, and 

 M. africanus. 



The numerous breeding places on the island beyond the limits of the inhabited 

 town, and again the mangrove and brackish swamps beyond the island itself across 

 the creeks to south and east, are doubtless capable of furnishing Lagos, at least 

 intermittently, with wind-blown mosquitos, and possibly some species rarely 

 found as larvae in the local sources may have their origin in these regions beyond. 



In the period dealt with in these notes which may be taken as from May 1914 

 to August 1918, the number of different species which have come to notice in Lagos 

 Municipal Area has been 46,f viz.: — 



Anophelinae. 

 Anopheles costalis, Theo., A. funestus, Giles, A. mauritianus, Grandpre, 

 A. obscurus, Griinb.,* A. nili, Theo.* 



CULICINAE. 



Banksinella punctocostalis, Theo.* 



Culex ataeniatus, Theo., C. consimilis, Newst., C. decens, Theo., C. duttoni, Theo., 

 C. fatigans, Wied., C. grahami, Theo., C. guiarti, Blanch., C. insignis. Carter, 

 C. pruina, Theo.,* C. quasigelidus, Theo.,* C. rima, Theo., C. salisburiensis, Theo., 

 C. sitiens, Wied., C. thalassius, Theo., C. tigripes, Grandpre, C. univittatus, Theo.* 



f To these 46 may be added 10 species absent from this list but included amongst the 

 41 species recorded from Lagos and published in the pamphlet of the Yellow Fever 

 (West Africa) Commission, " Distribution of Mosquitoes in West Africa," Aug. 1913, 

 viz. Anopheles pharoensis, Theo., Aedomyia africana, N.L., Banksinella lineatopennis, 

 Ludl., Eretmopodites inornatus, Newst., Mimomyia mimomyiafonyiis, Newst., Ochlero- 

 tatus longipalpis, Griinb., O. marshalU, Theo., Stegomyia apicoargentea, Theo., Toxorhyn- 

 chites brevipalpis, Theo., Uranotaenia mashonaensis, Theo. 

 ni3) p 



