Concerning the plumage of this species Mr. Barrows writes:--"Late in March, 1881, we found this species in large flocks on the Pigué, and it was a beautiful sight to see a hundred or more fluttering about among the snowy plumes of the pampas grass, and displaying their rich black and yellow dress. Unlike most other birds obtained at that time, their plumage seemed nearly as bright and fresh as in summer." 99. AGELÆUS RUFICAPILLUS, Vieill. (RED-HEADED MARSH-BIRD.) +Agelæus ruficapillus+, _Scl. Cat. B._ xi. p. 347. +Xanthosomus ruficapillus+, _Scl. et Salv. P. Z. S._ 1869, p. 159 (Buenos Ayres); _iid. Nomencl._ p. 37; _White, P. Z. S._ 1882, p. 602 (Salta, Catamarca). +Chrysomus frontalis+, _Burm. La-Plata Reise_, ii. p 492 (Paraná). _Description._--Glossy blue-black; crown of head and middle of throat dark chestnut; bill and legs black: whole length 7·5 inches, wing 3·7, tail 2·9. _Hab._ Argentina and Paraguay. The sexes are alike in this species: the crown of the head is rufous, and with this exception the whole plumage a rich glossy blue-black. The beauty of the bird and its delicate, plaintive voice would no doubt make it a favourite with man if he saw more of it, only it lives and breeds in marshes, and does not come near his habitations. The Red-heads are gregarious and migratory. The flock can scarcely be said to break up in the breeding-season, as the birds all make their nests near together in the reeds. The nest is placed about one or two feet above the water, is about six inches in depth, and made of leaves and aquatic grasses woven together. The eggs are four, pointed, with a white or pale bluish ground, and spotted with black at the larger end. The song of the Red-head is quite unique in character. It begins with a low, hollow-sounding note, then the voice changes to a clear, sorrowful tone, rising in a rapid succession of short notes, and falling again in longer ones. After the breeding-season the birds fly about in flocks of two or three hundred individuals, and sing in concert on the trees. Their chirp has a peculiar metallic sound, and can be imitated by tapping on the edge of a copper bell with the finger-nail. 100. LEISTES SUPERCILIARIS, Bp. (RED-BREASTED MARSH-BIRD.) +Leistes superciliaris+, _Hudson, P. Z. S._ 1870, p. 333 (Buenos Ayres); _Scl. et Salv. Nomencl._ p. 38; _Durnford, Ibis_, 1877, p. 175 (Buenos Ayres); _White, P. Z. S._ 1882, p. 602 (Salta); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 136 (Entrerios); _Scl. Cat. B._ xi. p. 349. +Trupialis guianensis+, _Burm. La-Plata Reise_, ii. p. 490 (Banda Oriental).