Hans v. Berlepsch has lately shown that Azara described this species under the designation "_Picaflor cola de topacio_," and that it must consequently bear the name _ruficollis_ of Vieillot, instead of _chrysura_ of Lesson, by which it is more commonly known. It visits the more northern portion of the Argentine Republic, and was obtained in the vicinity of Buenos Ayres by Hudson at Conchitas, and by Durnford at Punta Lara. The British Museum contains specimens from both these localities. 239. HYLOCHARIS SAPPHIRINA (Gm.). (RED-THROATED HUMMING-BIRD.) +Hylocharis sapphirina+, _Scl. et Salv. Nomencl._ p. 93; _Durnford, Ibis_, 1877, p. 184 (Buenos Ayres); _Barrows, Auk_, 1884, p. 22 (Entrerios); _Elliot, Syn. Troch._ p. 236; _Gould, Mon. Troch._ v. pl. 342. _Description._--Head, upper surface and under wing-coverts, flanks and abdomen rich deep shining green; chin rufous chestnut; fore part of the neck and breast rich sapphirine blue, with violet reflexions; upper tail-coverts bronzy brown; tail-feathers chestnut, the two centre ones with a bronzy hue, the remainder edged with blackish brown; wings purple-brown; under tail-coverts light chestnut; bill fleshy red, except at the point, which is black; feet brown: whole length 3·5 inches, wing 2·2, tail 1·2. _Female_: upper surface green as in the male, crown approaching to brown, throat pale rufous; only a trace of the blue on the throat; under surface much paler, fading into white on the centre of the abdomen; tail-feathers dark brown, the lateral ones tipped with greyish, and the middle feathers glossed with deep bronze. _Hab._ Southern Brazil, Paraguay, and Northern Argentina. The Red-throated Humming-bird is abundant in the woods along the Plata river, and ranges, I believe, fifty or sixty miles south of Buenos Ayres city. Outside of the littoral woods it is very rarely met with. The only nest I have found was in my own garden, and was placed on a horizontal branch. The female continued sitting on the nest, which contained two eggs, even when I placed my hand almost touching it; the male bird in the mean time exhibiting the greatest anxiety, and hovering so near as almost to brush my face with its wings. 240. CHLOROSTILBON SPLENDIDUS (Vieill.). (GLITTERING HUMMING-BIRD.) +Chlorostilbon splendidus+, _Durnford, Ibis_, 1877 p. 184 (Buenos Ayres); _Salvin, Ibis_, 1880, p. 360 (Salta); _White, P. Z. S._ 1882, p. 616 (Catamarca); _Barrows, Auk_, 1884, p. 22 (Entrerios); _Elliot, Ibis_, 1877, p. 136; _id. Syn. Troch._ p. 244. +Ornismya aureoventris+, _d'Orb. et Lafr. Syn. Av._ ii. p. 28 (Corrientes). +Chlorostilbon aureiventris+, _Scl. et Salv. Nomencl._ p. 94. +Hylocharis bicolor+, _Burm. La-Plata Reise_, ii. p. 448 (Mendoza, Paraná, Tucuman). +Chlorostilbon phaethon+, _Gould, Mon. Troch._ v. pl. 354.