The nest is deep, well-built, and well-concealed, sometimes resting on the ground, but frequently raised above it. It contains five long, pointed eggs, with a white or bluish-white ground-colour, and thickly spotted with brown. I have, frequently found the eggs of the _Molothrus_ in its nest, but have never been able to see this Sparrow feeding, or followed by, a young _Molothrus_. Possibly, if it ever hatches the parasitical egg at all, the voracious young Cow-bird is starved by the delicate food supplied by its foster-parents. 92. OROSPINA PRATENSIS, Cab. (MEADOW SEED-FINCH.) +Orospina pratensis+, _Cab. Journ. f. Orn._ 1883, p. 108, tab. i. fig. 1. _Description._--Cap dark greenish yellow; rump yellowish green; remainder of upper parts dark brown, feathers of interscapulium and of wings and tail edged with yellowish green; inner webs of the outer pair of tail-feathers almost wholly white, the next pair with a large white spot; under surface yellow, lightest on the throat, middle of belly, and crissum; flanks greenish: total length 4·5 inches, wing 2·5, tail 1·8. _Hab._ Tucuman. Herr Schulz discovered this little Finch, which Dr. Cabanis has referred to a new genus allied to _Sycalis_, upon the high Sierras of Tucuman, where it was observed sitting on the stones. Fam. XI. ICTERIDÆ, or TROUPIALS. The Icteridæ or Troupials constitute a large group of Passerine birds allied to our Starlings (_Sturnidæ_), of which they take the place in the New World. They are at once structurally distinguishable from the Starlings by having only 9 primaries in the wing, just as the Mniotiltidæ of the New World are in a similar manner distinguishable from the Sylviidæ. In America the Icteridæ play an important part, numbering some 130 species, and extending throughout the two continents from north to south. Of these, 15 species occur in Argentina, and amongst them are three species of Cow-bird (_Molothrus_), remarkable for their parasitic habits, of which Hudson's observations have enabled him to give a full and, for the first time, a tolerably complete account. 93. AMBLYCERCUS SOLITARIUS (Vieill.). (SOLITARY CASSIQUE.) +Cassicus solitarius+, _Scl. et Salv. Nomencl._ p. 36; _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 133 (Entrerios); _Scl. Cat. B._ p. 326. _Description._--Uniform black; bill white; feet black: total length 11 inches, wings 4·8, tail 4·5. _Female_ similar, but smaller. _Hab._ Peru, Bolivia, Brazil, Paraguay, and Northern Argentina. Mr. Barrows obtained a single specimen of this species at Concepcion, and others were seen. It was said to be an excellent song-bird, and to be more abundant further up the Uruguay River. 94. MOLOTHRUS BONARIENSIS (Gm.). (ARGENTINE COW-BIRD.)