Mr. G. R. Gray is induced to consider the species figured under the name of _T. Darwinii_, as the _T. striata, Gm._ and the _T. Darwinii_ of the Zoological Society’s Proceedings, as the female of the same species, while the young birds may be described as following: Brown, with the margins of the dorsal feathers greenish brown, those of the wings and tail margined brownish white; head and neck greyish green; beneath the body pale dusky green, somewhat darker on the breast and sides; uropygium yellowish green. Three specimens of this species are contained in the British Museum, exhibiting male, female, and young. 2. AGLAIA VITTATA. Tanagra vittata, _Temm._ Pl. col. Maldonado; not common. PIPILLO PERSONATA. _Swains_. PLATE XXXV. P. personata, _Swains_. Two cent. and a quart. p. 311. Maldonado; not common. The stomach of one, which I shot, contained seeds. EMBERIZOIDES POLIOCEPHALUS. _G. R. Gray._ _E. olivaceus, dorsi plumis medio nigro striatis; capite gulâque cinereis, priore plumis singulis, medio nigrostriatis; corpore infra rufescenti albo; hypochondriis tectricibus caudæ inferioribus obscurioribus; alarum margine latè flava, remigibus primariis secundariisque nigris; prioribus pallidè olivaceo, posterioribus olivascente flavo latè marginatis._ Long. tot. 7¾ unc.; _alæ_, 3½; _caudæ_, 4; _tarsi_, 1¼; _rostri_, 8 lin. Olivaceous, with the feathers of the back marked down the middle with black; the head and throat cinereous, with each feather of the former streaked down the middle with black; beneath the body rufous white, darker on the flanks and under tail coverts: the border of the wings bright yellow; the secondaries and primaries black, the former broadly margined with pale olive, the latter with bright olivaceous yellow; base of bill dusky orange. Habitat, northern shore of the Plata. (_May_ and _August_.) This bird is common both near Monte Video and Maldonado, in swamps. Stomach full of seeds: it makes a shrill loud cry: its flight is clumsy, as if its tail were disjointed. FAM.—COCCOTHRAUSTINÆ. GENUS, GEOSPIZA, _Gould_. _Corporis figura brevissima et robusta._ _Rostrum magnum, robustum, validum, altitudine longitudinem præstante; culmine arcuato et capitis verticem superante, apice sine denticulo, lateribus tumidis._ _Naribus basalibus et semitectis plumis frontalibus._ [Illustration: _Birds. Pl. 35._ _Pipilo personata_ ] _Mandibulâ superiori tomiis medium versus sinum exhibentibus, ad mandibulæ inferioris processum recipiendum. Mandibula inferior ad basin lata, hoc infra oculos tendente. Alæ mediocres remige primo paulo breviore secundo, hoc longissimo._ _Cauda brevissima et æqualis._