Abstract
A batch of Toxorhynchites brevipalpis brevipalpis (Theobald) of uniform age was reared from egg to adult under controlled conditions in the laboratory. Diel patterns of pupation and emergence, and duration of larval and pupal stages, were recorded for males and females separately. Pupation showed no detectable diel periodicity, but emergence was almost exclusively diurnal and occurred most frequently during the middle six hours of the 12-hour photophase. T. b. brevipalpis is exceptional among mosquitoes in being protogynous at emergence, although it is not protogynous at pupation: the earlier emergence of females reflects the shorter duration of their pupal stage.