_Xanthornus bullocki_, SW. Syn. Mex. Birds, Taylor’s Phil. Mag. I, 1827, 436. _Agelaius bullocki_, RICH. Rep. Brit. Assoc. 1837. _Icterus bullocki_, BON. List, 1838.—AUD. Orn. Biog. V, 1839, 9, pls. ccclxxxviii and ccccxxxiii.—IB. Birds Am. IV, 1842, 43, pl. ccxviii.—NEWBERRY, Rep. P. R. R. VI, IV, 1857, 87.—BAIRD, Birds N. Am. 1858, 549.—MAX. Caban. J. VI, 1858, 259.—LORD, Pr. R. A. Inst. IV, 121.—COOPER & SUCKLEY, 209.—SCLATER & SALVIN, Ex. Orn. I, 1869, 188 (diagnosis).—COOPER, Orn. Cal. 1, 1870, 273. _Psarocolius auricollis_, MAXIM. Reise Nordam. I, 1839, 367 (Fort Pierre, Neb.). _Hyphantes b._, CASS. Pr. A. N. S. 1867, 62.—HEERM. X, _S_, 52 (nest). SP. CHAR. Tail very slightly graduated. Upper part of the head and neck, back, wings, two central tail-feathers, line from base of bill through the eye to the black of the nape, and a line from the base of the bill running to a point on the throat, black. Under parts generally, sides of head and neck, forehead and line over the eye, rest of tail-feathers, rump, and upper tail-coverts, yellow-orange. A broad band on the wings, involving the greater and middle coverts, and the outer edges of the quills, white. Young male with the black replaced by greenish-yellow, that on the throat persistent; female without this. The first plumage of the young differs from that of _baltimore_ in being more whitish beneath; lighter olive above, and without dark spots on back; white of middle and greater coverts connected by white edges of the latter. Length, about 7.50 inches; wing, 3.80. HAB. High Central Plains to the Pacific; rare on Upper Missouri; south into Mexico. City of Mexico (SCL. & SALV. 1869, 362). A closely allied Mexican species is _I. abeillei_ of Lesson, differing principally in having the sides and rump black. HABITS. Bullock’s Oriole, the western counterpart of the eastern Baltimore, is found throughout the Pacific shore, from the great Central Plains to the ocean, and from Washington Territory to Mexico. It is not given by Sumichrast as occurring in Vera Cruz, where its place is taken, as a migrant, by the Baltimore. It was not noticed by Mr. Dresser on the Rio Grande, but in Arizona it was found by Dr. Coues to be a common summer resident. It was there seen to frequent, almost exclusively, the willows and cottonwoods of the creek-bottoms. To the small twigs of these trees its pensile nests were usually attached. It is said to arrive in Arizona late in April, and to remain there nearly through September. In the survey of the Mexican boundary Dr. Kennerly met with this species in passing through Guadaloupe cañon, where it was often seen, but it was observed at no other point on the route. It seemed to prefer the low bushes on the hillside to the large trees. In its motions it was quick and restless, passing rapidly from bush to bush.