Turdus pallasi, var. auduboni, BAIRD. ROCKY MOUNTAIN HERMIT THRUSH. _Turdus auduboni_, BAIRD, Rev. Am. Birds, 1864, 16.—RIDGWAY, P. A. N. S. 1869, 129.—ELLIOT, Illust. (fig.). _Merula silens_, SWAINSON, Philos. Mag. I, 1827, 369 (not _Turdus silens_ of VIEILLOT, Encycl. Méth. II, 1823, 647, based on _T. mustelinus_, WILS. = _T. fuscescens_).—IB. Fauna Bor.-Amer. II, 1831, 186.—BAIRD, Birds N. Amer. 1858, 213, and 922.—SCLATER, P. Z. S. 1858, 325 (La Parada), and 1859, 325 (Oaxaca).—IB. Catal. Am. Birds, 1861, 2, no. 9. SP. CHAR. Colors much as in _Turdus nanus_, but the upper tail-coverts scarcely different from the back. Tail yellowish-rufous. Length of wing, 4.18; tail, 3.60; bill from nostril, .45; tarsus, 1.26. HAB. Rocky Mountains, from Fort Bridger south into Mexico. Orizaba (Alpine regions), SUMICHRAST. This is a very distinct race of thrushes, although it may be questioned whether it be truly a species. It is, however, sufficiently distinct from the eastern and western Hermit Thrushes to warrant our giving it a place of some kind in the systems. The young plumage differs from that of _pallasi_ as do the adults of the two, and in about the same way. The olive is very much purer, with a greenish instead of a brownish cast, and the tail is very much lighter, inclining to dull ochraceous instead of rufous; this yellowish instead of rufous cast is apparent on the wings also. The yellowish “drops” on head, back, etc., are very much narrower than in _pallasi_, while the greater coverts, instead of being distinctly tipped with yellowish, merely just perceptibly fade in color at tips. HABITS. At present we have but little knowledge of the habits of this form of _T. pallasi_, and no information whatever regarding its nesting or eggs. In its distribution it is confined to the central range of mountains from Fort Bridger to Southern Mexico. This species, there known as “Solitario,” is common in the Alpine region of Vera Cruz (as well as in all the elevated regions of Central Mexico), frequenting the pine woods in the district of Orizaba. Mr. Sumichrast obtained it at all seasons of the year at Moyoapam, in that vicinity; a locality the height of which approximates 2,500 metres. It is also found at a height of 1,200 metres, near the city of Orizaba.