(syn. Melanerpes Ϯ Acorn Woodpecker M. formicivorus) Gr. βαλανος balanos acorn; σφυρα sphura, σφυρας sphuras hammer, mallet; "Balanosphyra gen. nov. (Picidæ). Type. — Picus formicivorus Swainson. Medium sized Picidæ similar to Melanerpes but with antrorse prefrontal feathers ("nasal tufts") developed into conspicuous dense tufts; feathers of breast broad, imbricated, and firm; eighth, seventh and eighth, or sixth, seventh and eighth primaries longest; ninth primary nearly as long as fifth, and tenth (outermost) relatively much smaller (only about one-fourth as long as ninth), narrower, and more acuminate. (βαλανος, an acorn; σφυρα, a hammer.)" (Ridgway 1911).