The nest is made in a dark hole in a wall or tree, sometimes in the forsaken domed nest of some other bird; and where such sites are not to be found, in a dense thistle or thorn-bush, or in a large tussock of grass. I have also found nests in dry skulls of cows and horses, in an old boot, in the sleeve of an old coat left hanging on a _fence_, in a large-necked bottle, and in various other curious situations. The nest is built of sticks and lined with horse-hair or feathers, and the eggs are usually nine in number, of a pinkish ground-colour, thickly spotted with pale red. 13. TROGLODYTES AURICULARIS, Cab. (EARED WREN.) +Troglodytes (Uropsila) auricularis+, _Cab. Journ. f. Orn._ 1883, p. 105, t. ii. fig. 1. _Description._--In habit and size near the European Wren, _T. parvulus_, but peculiar for the blackish-brown hinder half of the ear-coverts and its broad white superciliaries. Upper surface and flanks brown; throat and middle of belly whitish, tinged with brownish yellow; wings and tail with fine black cross bands; crissum with broader black and white cross bands. (_Cabanis._) _Hab._ Tucuman. This is a recent discovery of Herr Schulz in the Sierra of Tucuman. We have not yet met with specimens of it. 14. CISTOTHORUS PLATENSIS (Lath.). (PLATAN MARSH-WREN.) +Cistothorus platensis+, _Scl. et Salv. P. Z. S._ 1869, p. 158; _iid. Nomencl._ p. 7; _Durnford, Ibis_, 1877, p. 168 (Buenos Ayres); _Döring, Exp. al Rio Negro, Zool._ p. 37 (R. Sauce, R. Colorado, R. Negro); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 87 (Carhué); _Sharpe, Cat. B._ vi. p. 244. +Cistothorus fasciolatus+, _Burm. La-Plata Reise_, ii, p. 476 (Mendoza). _Description._--Above pale sandy brown, variegated with black streaks; head darker brown, streaked with black; the hind neck paler brown, with narrow black streaks; wing-coverts brown; tail-feathers dark sandy brown, barred with blackish brown; under surface pale sandy buff: total length 4·3 inches, wing 1·85, tail 1·6. _Female_ similar. _Hab._ Argentina, Patagonia, and Falkland Islands. This small Wren is rarely seen, being nowhere common, although widely distributed. It prefers open grounds covered with dense reeds and grasses, where it easily escapes observation. I have met with it near Buenos Ayres city; also on the desert pampas, in the tall pampas-grass. It is likewise met with along the Paraná river, and in Chili, Patagonia, and the Falkland Islands. In the last-named locality Darwin found it common, and says that it has there an extremely feeble flight, so that it may easily be run down and taken.