The lack of basiconic antennal sensilla in the mutant lozenge was used to assess the role of these olfactory receptors in the courtship behavior of Drosophila melanogaster. Under normal light conditions, lozenge males courted virgin females much less than wild-type males did. However, when visual courtship stimuli were eliminated by studying behavior under dim red light, the two kinds of males courted individual wild-type virgin females with the same intensity, and the latency to copulation was similar. Also, no difference in courtship vigor was observed if the two kinds of males were paired in red light with a mated female. These data suggest that antennal basiconic sensilla are important for neither the perception of the attraction pheromone(s) of virgin females nor the inhibitory pheromone(s) of mated females. Similar assays with males deprived of maxillary palps make it unlikely that the basiconic-like sensilla on these appendages are needed to perceive the attraction pheromones. However, the unexpectedly high courtship activity of palp-deprived males toward mated females suggests that basiconic-like maxillary sensilla may be receptors of inhibitory female compounds.