Rostrum free, not supported by either the prosternum or the basal segments of the appendages.
Its rostrum is unusually long, being five-sixths of the body length in the female, and slightly shorter in the male.
Ia, frons; b, clypeus (the pointed labrum beneath it); II, mandible; III, first maxilla; (a, base; b, sheath; c, piercer), III', inner view of sheath; IV, second maxillae forming rostrum (b, mentum; c, ligula).
Mandibles and first maxillae modified as piercers; second maxillae fused to form a jointed, grooved rostrum.
Within the groove of the rostrum two pairs of slender piercers - often barbed at the tip - work to and fro.