Sensilla on the mouthparts and antennae of the elephant louse, Haematomyzus elephantis Piaget (Phthiraptera: Haematomyzidae)

The labial palpus of the elephant louse Haematmyzus elephantis has six sensilla that represent three different types: trichoid, basiconic, and styloconic. Two rows of basiconic sensilla are situated on the dorsal and the ventral surfaces of the rostrum, and each row consists of three sensilla. Male and female antennae have 15-17 trichoid sensilla situated on the scape, pedicel, and three antennal annuli. Both sexes have two sensilla basiconica on the dorsal surface of the pedicel near the junction of the scape and pedicel. Two coeloconic (tuft) sensilla are situated on the antennae of both sexes, one sensillum on each of the last two annuli. There are three plate organs, two on the last annulus and one on the penultimate annulus of the male and female antennae. Sexual dimorphism is exhibited in the male and female antennae, in that the male has about twice as many sensilla basiconica on the apex of the last annulus as does the female. The total number of sensilla basiconica on the apex of the male antennae is at least two times the number that is known to be present in any other species of lice.