The upper plumage is olive-green; the entire under surface and a stripe on the side of the head pure yellow; wing and tail-quills dark. Total length 6-1/4 inches. 126. CNIPOLEGUS ANTHRACINUS, Heine. (ASHY-BLACK TYRANT.) +Cnipolegus anthracinus+, _Scl. et Salv. Nomencl._ p. 43; _Salv. Ibis_, 1880, p. 356 (Salta); _Döring, Exp. al Rio Negro, Zool._ p. 24 (Patagonia). +Cnipolegus aterrimus+, _White, P. Z. S._ 1882, p. 604 (Misiones). +Cnipolegus hudsoni+, _White, P. Z. S._ 1883, p. 39 (Cordova)? +Myiarchus fasciatus+, _Leybold, J. f. O._ 1865, p. 402 (Mendoza), ♀. _Description._--Above dull black, a broad bar across the vanes of the inner webs of the wing-feathers white; bill plumbeous; feet black: whole length 6·3 inches, wing 3·5, tail 3·0. _Female_ ashy brown; rump, upper tail-coverts, and basal portions of tail bright rufous; wings blackish, with two white transverse stripes; beneath pale fulvous, white on the belly; bill and feet black. _Hab._ Northern Argentina. Unfortunately very little is yet known about the habits of these interesting little Tyrant-birds, for which I should like to suggest the common name "_Spectacular_," for reasons I shall say more about when I come to describe the _Lichenops perspicillatus_, a species which undoubtedly belongs to this peculiar well-defined group. The plumage of the male is, in most cases, intensely black, and there is a pure white bar on the remiges, hidden when the bird is perched, and when it flies made doubly conspicuous by the peculiar motion of the wings. In all the known species the female has a dull brown plumage, lined or mottled with dusky tints, and with some portion of the wing-quills marked with rufous or chestnut colour. The Ashy-black Tyrant inhabits the Mendoza district, and is also a summer visitor in Patagonia, where it was obtained by Dr. Döring. Speaking of its habits, he says the male is solitary, perches on the summit of a bush or dry twig, emits at intervals a song or call composed of two syllables, plaintive and flute-like in character, and uttered while the bird rises up a few feet into the air. During this performance the white bands on the wings are displayed conspicuously and a humming sound is produced. 127. CNIPOLEGUS HUDSONI, Scl. (HUDSON'S BLACK TYRANT.) +Cnipolegus hudsoni+, _Scl. P. Z. S._ 1872, p. 541, pl. xxxi. (Rio Negro). _Description._--Uniform dull black; a broad bar across the bases of the inner webs of the wing-feathers white; two outer primaries much pointed at their extremities; bill plumbeous, feet black: whole length 6·0 inches, wing 2·8, tail 2·6. This species is at once distinguishable from the preceding (_C. anthracinus_) by its smaller size and the peculiar narrowed outer remiges. _Hab._ Northern Patagonia.