Observations additional to those made by Dunn (1927) of Culicine mosquitos breeding in “ test ” water containers about a Compound in Southern Nigeria, near Lagos, are here reported for a period of the year (June to December) not covered in Dunn's study. Only the optimum type of container mentioned in Dunn's report (bamboo joints containing water and mango leaves) was employed, and these were placed in the same ten representative environmental situations. The numerical rank of infesting species differed significantly in the two studies only in the case of Culex decens, which dropped from third to last place, and of Aëdes africanus, which rose from tenth to sixth place. The total numbers of infestations in the former study were greater, but this is explainable on the basis of one or several variables, i.e., seasonal differences, elapse of time between studies, or less probably the fact that there were four containers instead of one at each station. The number of infestations at any one station has little relation to the number of resultant adults; there is a wide variation in these numbers.

An analysis of the occurrence of A. aegypti in containers and a discussion of certain bionomical information together with relative weather conditions are included. Brief data are also presented of the incidence of species at three additional stations, one in a centre of dense population (Lagos), one in a suburb (Ebute Metta), and the third isolated in dense “ bush.”