This bird generally frequents marshy grounds. I procured specimens from La Plata and from Chile; in the latter country it extends at least as far north as the valley of Copiapo, in 27° 20′: on the eastern plains it does not range, according to Azara, north of 28°. It builds in reeds. Molina says it is called by the Indians Thili, or Chile—hence he derives the name of the country. [Illustration: _Birds. Pl. 44._ _Certhidea olivacea._ ] [Illustration: _Birds. Pl. 45._ _Xanthornus flaviceps._ ] 2. XANTHORNUS FLAVUS. _G. R. Gray._ PLATE XLV. Oriolus flavus, _Gmel._ Psarocolius flaviceps, _Wagl._ Syst. Avium. Troupiale à tête jaune, _Azara_, No. 66. This species is common at Maldonado in large flocks. LEISTES ANTICUS. _G. R. Gray._ Icterus anticus, _Licht._ Cat. p. 19. Agelaius virescens, _Vieill._ Ency. Meth. 543. Psarocolius anticus, _Wagl._ Le Dragon, _Azara_, No. 65. This bird is exceedingly abundant in large flocks on the grassy plains of La Plata. It is noisy, and in its habits resembles our starling. 1. AGELAIUS FRINGILLARIUS. _G. R. Gray._ Icterus fringillarius, _Spix_, Av. Sp. No. 1. t. lxv. fig. 1 & 2. p. 68. Psarocolius sericeus, juv., _Wagl._ This species is rare at Maldonado, but appears more common on the banks of Parana in Lat. 31°. S. Spix says (vol. i. p. 68, Birds of Brazil), it is found in Minas Geraes. 2. AGELAIUS CHOPI. _Vieill._ Turdus curæus, _Gmel._ Le Chopi, _Azara_, No. 62. Icterus unicolor, _Licht._ Icterus sulcirostris, _Spix_, Av. Br. pl. 64. f. 2. This species is common in flocks on the pasture grounds of Chile, and along the whole western shore of the southern part of the continent. In Chile it is called, according to Molina, “cureu.” It is a noisy, chattering bird, and runs in the manner of our starlings. It can be taught to speak, and is sometimes kept in cages. It builds in bushes. MOLOTHRUS NIGER. _Gould._ Tanagra bonariensis, _Gmel._ Icterus niger, _Dand._ Passerina discolor, _Vieill._ Icterus maxillaris, _D’Orb. & Lafr._ Icterus sericeus, _Licht._ Psarocolius sericeus, _Wagl._