Examples of this wide-ranging species, obtained by Döring in Tucuman, are referred by Dr. Cabanis to his subspecies "_latirostris_," which seems to us hardly distinct from _S. cineracea_. 120. FLUVICOLA ALBIVENTRIS (Spix). (WHITE-BELLIED TYRANT.) +Fluvicola albiventris+, _Scl. et Salv. Nomencl._ p. 43; _Durnford, Ibis_, 1878, p. 59 (Buenos Ayres). _Description._--Above black; front half of head, narrow band across the rump, and slight edgings to wing-coverts and outer secondaries white; below white; bill and feet black: whole length 5·5 inches, wing 2·8, tail 2·2. _Female_ similar. _Hab._ Amazonia, Bolivia, and Argentine Republic. The small black-and-white Tyrant is not uncommon in the marshes and on the river-margins in the Plata district, its spring migration extending south to Buenos Ayres. Like the Kingfisher, it haunts the water-side and is found nowhere else. It has a shy, retiring disposition, concealing itself in the close thickets overhanging a stream, so that one does not often see it, notwithstanding its conspicuous white plumage. When disturbed it emits a series of low ticking notes, or darts swiftly out from the thicket, showing itself for a moment over the water before disappearing once more into its hiding-place. D'Orbigny says it makes a purse-shaped nest, of slender twigs, moss, and feathers neatly interlaced, and lays four white eggs, spotted at the large end with brown. 121. ARUNDINICOLA LEUCOCEPHALA (Linn.). (WHITE-HEADED TYRANT.) +Arundinicola leucocephala+, _d'Orb. Voy., Ois._ p. 334 (Corrientes). _Description._--Black; whole head and neck and a patch on the flanks white; bill horn-colour, base of lower mandible white; feet black: whole length 5·0 inches, wing 2·5, tail 1·8. _Female_ above cinereous; front and sides of head whitish; tail black; beneath white, flanks and under wing-coverts cinerascent. _Hab._ Colombia and southwards to Argentina. This species, which is of wide distribution, was met with in Corrientes by d'Orbigny. 122. ALECTRURUS TRICOLOR, Vieill. (COCK-TAILED TYRANT.) +Alectrurus tricolor+, _Scl. et Salv. Nomencl._ p. 43. _Description._--Above black, rump greyish; sides of the head, scapularies, lesser wing-coverts, and outer margins of secondaries white; tail black, outer rectrix on each side produced, expanded, fan-shaped; below white, patch on each side of the breast (forming an incomplete collar) black; bill horn-colour; feet black: whole length 7·2 inches, wing 2·8; tail, outer rectr. 2·5, middle rectr. 1·5. _Female_: above brown, rump and lesser wing-coverts pale; beneath dirty white, sides of breast brown. _Hab._ S. Brazil, Paraguay, Uruguay, and Argentine Republic.