This species differs markedly in habits, language, and appearance from the last. In both sexes the colour is a uniform slaty grey; the tail, which the bird incessantly opens and flirts like a fan, is black; as in _S. subcristata_ there is a hidden spot of white under the loose feathers forming the crest. It frequents the borders of running streams, seldom being found far from a water-course; and it alights as often on stones or on the bare ground as on trees. Male and female are always seen together, for it pairs for life, and the migration, if it has any, is only partial. It flits restlessly along the borders of the stream it frequents, making repeated excursions after small winged insects, taking them in the air, or snatching them up from the surface of the water, and frequently returning to the same stand. While thus employed it perpetually utters a loud, complaining _chuck_, and at intervals the two birds meet, and, with crests erect and flirting their wings and tails, utter a series of trills and hurried sharp notes in concert. The nest is generally placed beneath an overhanging bank, attached to hanging roots or grass, a few inches above the water; but it is sometimes placed in a bush growing on the borders of a stream. It is a neat, cup-shaped, but rather shallow structure, thickly lined inside with feathers. The eggs are four, pointed, white or pale cream-colour, with black and grey spots at the large end. 148. ANÆRETES PARULUS (Kittl.). (TIT-LIKE TYRANT.) +Anæretes parulus+, _Burm. La-Plata Reise_, ii. p. 455 (Mendoza); _Hudson, P. Z. S._ 1872, p. 543 (Rio Negro); _Scl. et Salv. Nomencl._ p. 47; _White, P. Z. S._ 1883, p. 30 (Cordova); _Durnford, Ibis_, 1878, p. 395 (Centr. Patagonia); _Döring, Exp. al Rio Negro, Zool._ p. 43 (R. Negro, R. Colorado). _Description._--Above cinereous, with an olivaceous tint on the lower back; head black, front varied with white, elongated vertical crest black, sometimes varied with white; wings blackish, with slight whitish tips to the coverts and whitish margins to the outer secondaries; tail blackish, outer webs of external rectrices whitish; below pale straw-colour, white on the throat; throat and breast with numerous and well-marked black striations; bill and feet black: whole length 4·0 inches, wing 1·9, tail 1·8. _Female_ similar, but crest shorter. _Hab._ Argentine Republic, including Patagonia, Chili, Bolivia, Peru, and Andes of Ecuador.