_Description._--Head, upper surface, wing-coverts, and flanks bronzy green; throat and whole lower surface white; wings purplish brown; central tail-feathers bronzy green, lateral dull bronzy brown on the outer webs; inner webs and shafts white, the inner webs clouded with bronzy brown in the centre; bill black, lower mandible paler at the base: whole length 4·2 inches, wing 2·1, tail 1·3. _Female_ similar. _Hab._ Peru, Bolivia, and Northern Argentina. White obtained examples of this species at Fuerte de Andalgala, in Catamarca, in September 1880. They were feeding on the flowers of the "Idiondilla," which is one of the "Humming-bird-plants" of that district. "They are very swift and wild in their movements," he tells us, and "make a very loud hum," louder in fact than any other species with which he was acquainted. 237. LEUCOCHLORIS ALBICOLLIS (Vieill.). (WHITE-THROATED HUMMING-BIRD.) +Leucochloris albicollis+, _Gould, Mon. Troch._ v. pl. 291; _Elliot, Syn. Troch._ p. 200. +Thaumatias albicollis+, _Burm. La-Plata Reise_, ii. p. 448 (Tucuman). _Description._--Head, all the upper surface, wing-coverts, chin and sides of the neck, abdomen and flanks deep shining grass-green; on the centre of throat and breast a large patch of white; lower part of abdomen and under tail-coverts white; wings purplish brown; two middle tail-feathers deep shining grass-green, the remainder bluish black, the three outer ones tipped with white; upper mandible black; basal two thirds of the lower mandible fleshy, apical third brown; feet brown: whole length 4·2 inches, wing 2·3, tail 1·4. _Female_ similar. _Hab._ S.E. Brazil, Paraguay, and N. Argentina. Dr. Burmeister states that this species is found near Tucuman in company with _Calliperidia furcifera_ and _Petasophora serrirostris_; but we have no other authority for its occurrence within the limits of the Argentine Republic. 238. CHRYSURONIA RUFICOLLIS (Vieill.). (GOLDEN-TAILED HUMMING-BIRD.) +Chrysuronia ruficollis+, _Berlepsch, J. f. O._ 1887, p. 18. +Chrysuronia chrysura+, _Scl. et Salv. Nomencl._ p. 93; _Elliot, Syn. Troch._ p. 169 (Arg. rep.), _Gould, Monogr. Troch._ v. pl. 329. _Description._--Head, all the upper surface, wings, and tail-coverts of a golden hue, inclining to brown on the head; wings purplish brown; tail of a very rich golden lustre both above and beneath; chin buff; under surface grey, washed with a golden hue, which is richest on the flanks; vent and thighs white; under tail-coverts grey, with a slight golden lustre; bill fleshy, red at the base of both mandibles and dark at the tip; feet brown: whole length 4·2 inches, wing 2·2, tail 1·2. _Female_ similar. _Hab._ S. Brazil, Paraguay, and N. Argentina.