SIGNIFICANCE OF STEGOMYIA FASCIATA IN AVEhT AFRICA. 249 



Africa. But the reverse could equally well have taken place, and indeed some 

 authorities, Goeldi for example, regard the West Coast as an original home of 

 the Stegomyia, But whatever its origin, it has been long an inhabitant of the 

 West Coast. Evidence is in favour of its having greatly multiplied during 

 the 18th and 19th centuries, that is to say, during the period of the opening 

 up of the (yoast of Africa to Western civilisation. As soon as towns increased 

 in size and new ones sprung into existence, the Stegomyia was given enor- 

 mously increased opportunities for breeding, as compared with the primitive 

 periods. No doubt the mosquito, like yellow fever itself, incrensed with com- 

 mercial development until comparatively recently, when, thanks to scientific 

 research, steps were taken to wage war on the breeding places. We know that 

 the mosquito is present in Togoland, Dahomey, Nigeria, Gold Coast the 

 Cameroons, Sierra Leone, Gambia and Senegal. It has also been recorded 

 so it is stated, from German and British East Africa, and in Durban. 



In 1901 Major Ross, and in 1901 Dr. Prout, drew attention to the 

 prevalence of Stegomyia in Freetown. The late Dr. Dutton pointed out in 

 1902 that this mosquito was the species most commonly met with in Bathurst. 

 From recent observations carried out by Graham and others, there is no 

 doubt that Stegomyia fasciata is today the common mosquito of the 

 Coast towns. 



As yellow fever has again this year (1910) declared itself both on the 

 Gold Coast and in Sierra Leone, it is now a necessity, before it is too late 

 to take steps to ascertain accurately the prevalence and distribution of this 

 pest all over Africa. Yellow fever has penetrated to the Sudan, and it may 

 spread to the East C'oast and North of Africa, if not already there hi an 

 endemic form. 



I. The Stegomyia in Sierra Leone. 



Freetown. 



In 1901, Hoss pointed out the prevalence of Stegomyia fasciata and 

 organised mosquito brigades to do away with it and other mosquitos. 

 Dr. Prout also drew attention to its prevalence. 



This year, 1910, careful surveys have been made both by myself and 

 Dr. Kennen and his assistants, with the following results. 



In the month of August 1910, I made, wdth Dr. Kennen, the Senior 

 Sanitary Officer, a house to house investigation of Freetown and covered 

 altogether 200 houses with their yards and out-houses. 



The streets selected were representative of the various classes in Freetown 

 including the merchants' quarters, those of the small traders and Syrians 

 and the native residential quarters of the well-to-do and the poorest. The 

 200 houses and yards contained 87 barrels, 144 buckets, 50 earthen- 

 ware pots, ^Q tin cans, 17 stone jars, 121 odd receptacles and 27 wells. 

 Therefore, distributed amongst the 200 houses there were no less than 



BULL. ENT. RES. VOL. I. PART 4, DECEMBER I9IO. X 



