﻿192 J AS. J. SIMPSON — ENTOMOLOGICAL 



and is found in all varieties of water-vessels. It is hardy and not much affected 

 by environment, living in both clean and foul water witb equal facility. Its chief 

 natural enemy in these water-receptacles is the large carnivorous larva of Culex 

 tigripes var. fusca, Theo." 



In all, five species of this genus have been recorded from Southern Nigeria, 

 and it might be well to review the distribution of each of these. By far the 

 commonest, both as regards individuals in any one locality, and also in general 

 distribution, is S. fasciata, but it is far from probable that the records here given 

 are by any means exhaustive for the Colony. So far as can be judged at present, 

 this species is most abundant in the Niger delta region. It has been found at 

 Sapele, Warri, Forcados, Burutu, Brass, Akassa, Bonny, Opobo and Degema, 

 and may be said to be ubiquitous in this area. It is almost impossible from a 

 mere examination of specimens sent in by collectors to form any reliable estimate 

 of the relative abundance of the species as compared with the total mosquito 

 population, for collections made at different times of the day give different results 

 and a great deal also depends on the situations in which the mosquitos have been 

 caught. 



In the Western Province, S. fasciata has been recorded from Lagos, Yaba, 

 Oshogbo and Ilesha, while in the Eastern Province it has been caught at Calabar, 

 Ikot-Ekpene and Bende. It should be noted, however, that at all these places 

 considerable collecting has been done, and this may account for the apparent gaps 

 in the distribution, and it will probably be found, when the fauna of other regions 

 is better known, that it occurs all over the Colony. It has recently been taken at 

 Maidugari, near Lake Chad, in N. Nigeria, and at Geidam, on the edge of the 

 Sahara, where the climate and other conditions are extremely divergent from 

 those in, for example, the Niger delta. 



Stegomyia africana has been found at Lagos, Yaba, Oshogbo, Forcados and 

 Bende ; Stegomyia apicoargentea at Yaba and Bende ; Stegomyia luteocephala at 

 Yaba and Bende ; and Stegomyia sugcns at Oshogbo. 



It is probably too sweeping to say that S. fasciata is the most common mosquito 

 on the coast, because the records based on large collections of mosquitos made in 

 Southern Nigeria do not altogether bear this out. As has been noted, however, 

 this may in part be due to the method of collecting, and in part to the time and 

 situation chosen for such work. 



The danger is, however, none the less minimised by this, and every effort should 

 be made to exterminate the pest. As in the case of other mosquitos, measures 

 should be directed against the larvae. It is now well known that Stegomyia is a 

 " small receptacle " breeder and is not commonly found in the vicinity of swamps. 

 All vessels which might retain water ought to be inverted when not in use and 

 stringent efforts should be made to ensure that this is done in native compounds. 

 Further, it ought to be a punishable offence to have within a compound any 

 receptacle containing mosquito larvae of any description. Unfortunately, this 

 offence is not restricted to native quarters, and the servants of Europeans are 

 often offenders in this direction. To supplement this work, European residences 

 should be segregated from native villages. In this connection one might mention 

 that the town of Lagos is the most flagrant example of the intermingling of 

 native and European houses. 



