The eumenid Ancistrocerus antilope (Panzer) is scarce at flowers in early summer, but abundant by late summer. Samples systematically collected at flowers are strongly male biased while comparable samples reared from trap nests are female biased. This indicates that males spend a greater proportion of their time at flowers than do females. Females visit flowers for nectar, but the males also search flowers for mates. Mating is initiated at flowers, but may be completed elsewhere.