--While overhauling a number of Buteo skins a few months ago there was one which did not answer the tag B. swainsouL On comparing it with some dark phases of Buteo borealis calurus of the last month's collecting I found this particular skin to be a beautiful reelartistic phase of calurus. It is a female, number I446, coll. W. O. E., Haywards., Cal., August 20, I897. The general color of the plumage is a blackish brown over the whole body, with a purplish reflection on the back and wings; the edges of the feathers of the breast, belly and thighs washed with chestnut brown; thighs also sparsely mottled with the same color. The measurements are: length 22 inches, wing I7 inches; while another female taken December I8, I9O3, measures 23 inches in length, wing I84/ inches. This specimen compares more with some dark phases of ]3. swainsoul. The rufous tail is black-banded, twice as deep as in a typical red-tail, and is edged with same at end. The head and throat are rufous black, fore-breast more grayish, belly brownish black, thighs rufous, barred with black, wings dusky brown and black, edged and slightly barred with grayish white; upper and under tail-coverts similar to thighs. A slight purplish reflection is seen over the wings, but not so much as on the first bird described. In a large series of these hawks there are rarely two out of five but show a difference in the plumage color. Seven out of twelve before me run either to a light or dark phase; some with grayish backs, others with dark brownish black or chestnut. The throat, breast and belly run from ochraceous gray to reddish brown, chestnut and yellowish white.--W. OTTO EMERSON, Haywards, Cal.