This is distinguished by having a slenderer bill than Metopidius, no lappet, and a shorter hind claw, and also by the 1st and 4th primaries being produced at the end, the first into a filamentous lanceolate appendage about an inch long, the 4th into an attenuated point. There is a strong sharp spur on the wing at the bend. An important character of this genus is that the breeding-plumage is quite distinct from that worn at other seasons, and that, in the nuptial garb, which is assumed by a change of colour in the feathers without any moult, the tail-feathers are greatly elongated. Sexes alike in plumage at all times, but the female larger than the male.
A single species.