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J. W. SCOTT MACFIE AND A. INGRAM. 



Table II. 



The percentages in which the larvae of the various mosquitos occurred in the 

 native compounds at Accra (411 samples) and at Lagos (1043 samples). 



In the Annual Report of the Medical Research Institute, Yaba, for the year 1914, 

 Connal and Coghill summarise the results of their examinations of mosquito larvae 

 sent to them from Lagos by Dr. Dalziel. The larvae of ten species were obtained, 

 the six recorded by Graham, and in addition Culex insignis, C. grahami, Ochlerotatus 

 irritans, and 0. nigricephalus. It is not definitely stated, however, that all these 

 species were found breeding in native compounds, and it is possible that some may 

 not have been, for they specially mention the fact that 0. irritans was found in crab- 

 holes, a situation in which it occurs at Accra also. 



Seasonal Distribution. 



The number of samples examined at Accra during the twelve months from December 

 1914 to November 1915 was insufficient to reveal any seasonal variations, even if they 

 had occurred, especially as there was such a marked falling off in the number of 

 specimens during the last five months of the investigation. At the laboratory, 

 however, there were records of the examinations of the larvae sent by the Medical 

 Officer of Health extending back to 1912, and although these were imperfect and 

 discontinuous it was fomid possible to summarise them broadly as identifications of 

 Anophehns, Stegompa, and other Cuhcine mosquitos. The examination of the 

 larvae submitted during twelve consecutive months showed that A. costalis was the 

 only Anophehne mosquito found in such samples, S. fasciata almost the only 

 Stegomyia, and C. fatigans by far the most common other Culicine. If then there 

 had been any marked seasonal variations in the incidence of these three species of 

 mosquitos at Accra it would almost certainly have appeared in the combined results 

 of the examinations of larvae for the four years 1912 to 1915. 



