Antennal sensory receptors of the male mosquito, Anopheles stephensi.

It was shown by electron microscopy that antennae of male Anopheles stephensi have the same types of sensory receptors as the females, with sunken pegs (sensilla ampullacea and sensilla coeloconica), surface pegs (sensilla basiconica), hairs (sensilla trichodea), bristles and fibrillae (sensilla chaetica), and scolopidia in the Johnston's organ. Compared with the female, the male mosquito has fewer than half of the sensory cells in the flagellum, but many more in the Johnston's organ. The smaller number of flagellar sensory neurons in the male was due mainly to fewer sensory receptors of possibly olfactory types. Sensory cells of mechano- and thermoreceptors were present in almost identical numbers in both sexes, as only about 15% of the long fibrillae, abundant as whorls in the male mosquito, are innervated by a single neuron.