During June 1979, 9323 and 7548 laboratory-reared progeny of wild-caught female Anopheles culicifacies were released as pupae in a self-marking device positioned at a breeding site near a rural village in Punjab Province, Pakistan. The numbers of marked adults collected resting indoors the first afternoon following release were disproportionately lower than the numbers taken in subsequent recapture attempts. In addition, the proportion of virgin and nulliparous unmarked females resting indoors was unexpectedly low, indicating that half of the newly-emerged population may have rested outdoors. Relatively few pairings were observed at male swarms which formed at dusk in cattle-buffalo feed-lots, indicating most mating occurred elsewhere or at different times of the night.