This is a rare Finch, and its massive beak and rich blue plumage give to it a highly interesting appearance; but about its habits I have little to tell, for it is essentially a bird of the wild forest, seldom coming near the abodes of man, and being, moreover, shy in disposition, it is difficult to observe it even in its haunts. It is migratory, and is usually seen singly or in pairs, or in small companies of four or five individuals. The male sings, but his performance is merely a confused medley of chattering notes, uttered in so low a tone that they can scarcely be heard at a distance of twelve yards. 50. ORYZOBORUS MAXIMILIANI, Cab. (PRINCE MAX.'S FINCH.) +Oryzoborus maximiliani+, _Burm. La-Plata Reise_, ii. p. 488 (Tucuman); _Sharpe, Cat. B._ xii. p. 78. _Description._--Black; large alar speculum, axillaries, and under wing-coverts white; bill pale yellow; feet brown: total length 5·8 inches, wing 2·9, tail 2·5. _Female_ brown; beneath brownish ochraceous. _Hab._ S. Brazil, Paraguay, and Northern Argentina. This Finch is stated by Burmeister to occur near Tucuman. 51. SPERMOPHILA PALUSTRIS, Barrows. (MARSH FINCH.) +Spermophila palustris+, _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 82 (Concepcion); _Sharpe, Cat. B._ xii. p. 112. _Description._--Above, from bill to rump, clear bluish ash; below, from bill to middle of breast, including lower eyelid, ear-coverts, and sides of neck, pure white; rest of underparts, rump, and upper tail-coverts bright chestnut-red; wings and tail blackish brown, edged with whitish; inner secondaries black, their tips and outer edges broadly white; a white patch across the base of all the primaries except the first two; bill and feet black, iris dark: total length 4·50 inches, wing 2·18, tail 1·70. _Female_ above uniform greenish olive, obscurely streaked with dusky; below light yellowish buff; wings and tail nearly as in male, but duller. This small and beautiful Finch was discovered by Mr. Barrows in February 1880, on the Lower Uruguay. It inhabits the marshes, where the males are frequently seen pursuing each other in the pairing-season, occasionally pausing on the top of some tall grass to pour out their delightful song. In character this resembles that of the Black-headed Goldfinch; but has, Mr. Barrows says, a variety and sweetness far beyond the powers of that bird. It is just possible that Mr. Barrows's Finch may be Azara's unidentified _Chipiu pardo y canela_ (Apuntamientos, vol. i. no. 143), which has the same habits, living in the dense reed-beds of the Paraguayan marshes, and is also a delightful singer,--superior to the Goldfinch or Canary, Azara says. 52. SPERMOPHILA MELANOCEPHALA (Vieill.). (BLACK-HEADED FINCH.) +Spermophila melanocephala+, _Sharpe, Cat. B._ xii. p. 118.