A description of two apparently overlooked species of Flycatchers, of the genus Arses. By R. Bowdler Sharpe, F. L. S., F. Z. S. etc. Senior assistant, Department of Zoology, British Museum. If it were a rule in Ornithology that species could only be described from the male birds, it is quite certain that some very different birds would be unchronicled. It often happens that two allied species are quite distinct as regards the males, and yet the females and young are indistinguishable one from the other. Cases in which the males are alike and the respective females quite different, are far rarer in ornithology, and yet a very positive case occurs in the genus Edoliisoma among the Campophagidae and another instance may apparently be found in the genus Arses among the Flycatchers. In fact the species usually called Arses telescophthalmus from New Guinea has heen made to include two other species which seem quite different, and which we propose to found upon the female plumage alone.