Among the specimens of Neotropical Bees described by Friese and preserved in the Berlim Museum the following ones were studied, or synonymized, or to some of them given a new status and redescribed, namely: the specimen of Megacilissa pretiosa Friese, 1898, is considered the holotype of Ptiloglossa pretiosa. Ptilothrix ? similis Friese, 1899 is a synonym of Melitoma nudipes (Burmeister, 1876). Centris (Epicharis) pygialis Friese, 1899, is an independent species. the present specimen the holotype and Bahia the type locality. Centris (Epicharis) flava Friese, 1900 a widely distributed species in South and Central America, described from 'Brasilia' is also considered as an independent species. The specimen of Centris atra Friese, 1900, from San Antonio, Colombia, is Centris (Melacentris) aeneiventris Mocsary, 1899 and the specimen from Blumenau (Rio das Antas), SC, Brazil, at the Viena Museum, is the melanic form of Centris (Melacentris) dorsata Lepeletier, 1841, the true Centris atra Friese, 1900, belongs in the subgenus Ptilotopus Klug, 1810, and is recorded from Northern South Anerica to Central Brazil [North of the States of Minas Gerais and Goias]. Centris xylocopoides Fox, 1899, from Trinidad, confounded with C. atra belongs to Melacentris and compared with the type of Centris (Melacentris) braccata Packard, 1869, proved to be a synonym. Centris ruficauda Friese, 1900 is the melanic form of Centris (Melacentris) intermixta Friese, 1900. Because Centris atra, selected by Sandhouse as the type species of Melanocentris, is a Ptilotopus, and the type species of Ptilotopus Klug, 1810, - Ptilotopus americanus Klug, 1810 - was included by Friese among his Melanocentris, Melacentris new name is proposed for Melanocentris autorum. non Friese, 1900, with Centris dorsata Lepeletier, 1841, as the type species.