For some time I have doubted whether the existing determinations of certain of Walsingham's species of plumes, based on the revision of this family by Barnes and Lindsey, were correct. Through the kind offices of Messrs. Tams and Stringer of the British Museum of Natural History I have been furnished with drawings of the left claspers of the male genitalia of a number of Walsingham's types in the genus Oidaematophorus; a study of these drawings in connection with my own slide material has confirmed my suspicions and shown that in at least two cases there had been misidentifications by the above-mentioned authors. With a view to clarifying the situation somewhat in this extremely difficult group I offer the following notes.