(BF Eldridge) In an attempt to explain the effect of sublethal effects of DDT on the reproductive potential of mosquitoes, a study was made on the susceptibility of adult mosquitoes exposed as larvae to various sublethal doses of DDT. The experimental data showed that metabolism of DDT absorbed during early larval stages proceeds slowly during pupal and adult stages. In general, the experimental data do not explain the cause of an increase of reproductive potential as a result of larval exposure. However, the relatively slow metabolism in mosquito larval and adult stages suggest that mosquitoes may serve as a source of DDT and its metabolites in aquatic environments.