The true Argus Pheasants are large birds distinguished by the enormous development of the secondary quills, which are of great breadth, nearly twice as long as the primaries in males, and decidedly longer than the primaries in females, and by the long median tail-feathers of the males, more than twice the length of the next pair. There are 12 feathers in the tail, which is graduated; the tarsus is long, without any spur; and the sides of the face, the chin, throat, and fore parts of the neck are naked. The plumage is spotted with black, brown, buff, and white, forming singularly beautiful patterns.
Two species are known—one from South Tenasserim, the Malay Peninsula, and Sumatra, the other from Borneo ; a third is indicated by some feathers of unknown origin. An allied form, Rheinardtius ocellatus, is found in Tonquin.