The male is a solitary bird, and feeds chiefly on the ground, running rapidly about in open places like a _Muscisaxicola_. It is also frequently seen perched conspicuously on the summit of a tall stalk or bush, and occasionally making a dart into the air after passing insects, showing in this habit his relationship with the Tyrant-birds. But he perches on an elevation less to watch for insects than for the purpose of his curious spectacular performance. This highly eccentric habit is strikingly like that of _Cnipolegus hudsoni_; and I have no doubt that all the _Cnipolegi_ possess similar habits. Both birds perch on a conspicuous place, upright, motionless, and looking more like grotesque little automata than living things; they both also leave the perch suddenly, as if shot from it by means of a steel spring. This singularly sudden movement, and the motion of the wings, rapid as in the Humming-bird, or shut and opened alternately and exhibiting the white wing-colour in a series of flashes, seems related to the conspicuous white mark. In both species, also, the wings make a humming sound during flight. The motions of the Silver-bill are, however, in some respects different from those of the _Cnipolegus_. Springing from its perch at intervals, it darts vertically to a height of about fifteen yards, then turns a summersault, uttering at the same moment a shrill-sounding little cry, after which it drops down again and alights on its perch suddenly, as if jerked back to it, and there remains stiff, erect, and motionless as before. The nest is made of dry grass in a thistle-bush or clump of reeds, and is rather deep and cup-shaped. The eggs are four in number, white, and spotted at the larger end with dark red. 132. MACHETORNIS RIXOSA (Vieill.). (SHORT-WINGED TYRANT.) +Machetornis rixosa+, _Burm. La-Plata Reise_, ii. p. 458 (Paraná); _Scl. et Salv. P. Z. S._ 1868, p. 142; _iid. Nomencl._ p. 44; _Hudson, P. Z. S._ 1874, p. 173 (Buenos Ayres); _Durnford, Ibis_, 1877, p. 177 (Buenos Ayres); _Salvin, Ibis_, 1880, p. 357 (Salta); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 142 (Entrerios). _Description._--Above brownish olive; wings and tail brown, the latter terminated by a yellowish band; middle of cap occupied by a scarlet crest; beneath bright yellow, paler on the throat; bill and feet black: whole length 7·2 inches, wing 3·9, tail 3·5. _Female_ similar, but rather duller. Young without the scarlet crest. _Hab._ S.E. Brazil, Bolivia, Paraguay, Uruguay, and La Plata. This species, found in the open districts throughout South America, from Venezuela to Buenos Ayres, where it is quite common, has very interesting habits. It is seven inches and a half long, has a plump body, short wings, and long legs. The upper plumage is light brown, the throat, breast, and belly yellow, and the male has a concealed crest of a bright orange-red colour.