The eggs measure .67 by .50 of an inch in their average proportions, resembling somewhat those of the Carolina Wren, but having a lighter ground, with fewer and finer markings of slate and reddish-brown. The ground-color is of a pinkish-white. Mr. A. Boucard obtained specimens of these birds in the winter months, in the State of Oaxaca, Mexico, probably of the var. _leucogaster_. We learn from Mr. Ridgway that in Southern Illinois (as far north as latitude 38° 20′ 20″) this Wren is very abundant, and the most familiar species of the family. In certain localities (as in the Valley of the Wabash) it entirely replaces the _Troglodytes ædon_, the latter being wholly unknown. In its habits it is even more familiar than that species, always preferring the out-buildings, even in large towns, to the neighborhood of the woods, and still further increases its attractions by possessing a charming song, a real _song_, of sweet notes finely modulated, and uttered, generally, as the bird perches upon a fence or the stable roof, its head thrown back, and its long tail pendent as it sings. The confused, gabbling sputter of _T. ædon_, uttered as it pauses just for an instant in its restless hopping through the ivy, cannot be compared to the chant of liquid musical notes of this species, which resembles more nearly, both in modulation and power, that of the Song Sparrow (_Melospiza melodia_), though far superior to it. On ordinary occasions the note of Bewick’s Wren is a soft, low _plit_, uttered as the bird hops about the fence or stable, its long tail carried upright, and jerked to one side at each hop. In its movements it is altogether more deliberate and less restless than the _T. ludovicianus_, or _Troglodytes ædon_, neither of which it much resembles in motion, and still less in notes. The nest of this Wren is usually built about the out-houses, a mortise-hole or some well-concealed corner being generally selected. Old stables and ash-hoppers are especially frequented as nesting-places. Mr. Ridgway found one in the bottom of the conical portion of a quail-net which was hung up in a shed, and another in a piece of stove-pipe which lay horizontally in the garret of a smoke-house; another rested upon a flat board over the door of an out-house, while a fourth was placed behind the weather-boarding of a building. The nest is generally very bulky, though the bulk is regulated to suit the size of the cavity in which the nest is placed. Its materials are usually sticks, straws, coarse feathers, fine chips, etc., exteriorly fastened together with masses of spider’s-webs, the lining being of finer and more downy materials, generally soft spider’s-webs, tow, and especially the downy feathers of barnyard fowls. Thryothorus bewickii, var. leucogaster, GOULD.