(syn. Picoides Ϯ Eurasian Three-toed Woodpecker P. tridactylus) Gr. negative prefix α- a- ; πτερνη pternē heel, foot; "Plumage black and white; feet three-toed. Apternus.* ... * We have not considered it expedient to adopt the name of Tridactylia, given, in a modern compilation, to all the three-toed Woodpeckers indiscriminately, since it would obviously lead to much confusion. Besides, we have long had the genus Tridactylus in Entomology. ... Sub-genus, Apternus Ϯ, pl. 56, SWAINS. ...Ϯ Th. α, priv., et πτερνα, calx" (Swainson 1831).