Gen. Char. Very similar in general form to Heliopædica, but the tail emarginated, instead of rounded, the feathers narrower and less rounded at the ends. The coloration quite different. Sexes alike, in all the species. Color nearly uniform green, with the anal region white, the wings and tail dusky. Many species with the whole lower parts, except laterally, pure white. One species (T. chionurus) with the tail white, except the ends of the feathers and the intermediæ.
The species are all of rather small size and rather plain appearance, from the uniformity of their green, or green and white, coloring. They belong to northern South America, and to Central America north to Guatemala.
The genus is included in the North American fauna solely upon the accidental occurrence of one species (T. linnæi) in Eastern Massachusetts.
Thaumatias linnæi, Bonap.
LINNÆUS’S EMERALD.
Thaumatias linnæi, Bonap. Rev. et Mag. de Zoöl. 1854, 255. Thaumatias l. Gould, Monog. Trochilid. pl. ? Trochilus tobaci, Gmel. Syst. Nat. I, 498. ? Trochilus tobagensis, Lath. Ind. Orn. I, 316. ? Trochilus tobago, Shaw, Gen. Zoöl. viii, 350. Ornismya viridissima, Less. Hist. Nat. 257, pl. lxxv. ? L’Oiseau-mouche à poitrine verte (Trochilus maculatus), Aud. et Vieill. Ois. Dor. tom. I, 87, pl. xliv. Argyrtria maculata, Maynard, Birds E. Mass. 1870, 128 (Cambridge, Mass.!).
Sp. Char. Continuous green, darker above, more brilliant, and of an emerald tint on the throat and jugulum; crissum, anal region, and middle of the abdomen, white. Primaries plain dusky. Tail blackish, with a faint reflection of dark blue subterminally, and of dull green basally, the lateral feathers obscurely tipped with dull dark ashy. Sexes alike. Wing, about 2.00; bill, .70.
Hab. Northern Brazil, Guiana, Tobago, and Bogota (Gould)?? Accidental in the eastern United States (Cambridge, Mass., Maynard).
This race much resembles the T. albiventris, (Reichenb.) Bonap. (Gould, Monog. Troch., Vol. V, p. ccci), of Brazil, but is said to be smaller and with less white on the abdomen and the under tail-coverts tinged with gray.