Taking the series from Eastern Mexico (Orizaba and Mirador) and northward along the Rocky Mountains of the United States, we find the black of the head continuous, sharply defined by a gently curved outline behind, and without a trace of either the vertex or post-ocular stripes. This is the true _melanocephalus_, as restricted, and may be regarded as the Rocky Mountain form. The most western specimen is 11,241, from Fort Bridger; the most northern (19,355), from Stinking River, Northern Wyoming. All specimens from the Pacific coast eastward to the western base of the Rocky Mountains, including Cape St. Lucas and Western Mexico south to Colima, differ from the Rocky Mountain series in having the posterior outline of the black hood ragged, and irregularly indented by the rufous of the nape, which always extends in a quite broad stripe toward the eye, along the side of the occiput, and quite frequently forms a conspicuous median vertex stripe, though the latter feature is sometimes not distinct. These differences are observable only in the males, and, although apparently slight, are yet sufficiently constant to justify distinguishing them as races. The Rocky Mountain form being the true _melanocephalus_, the name _capitalis_ is proposed for the western one. HABITS. This bird occurs from the high Central Plains to the Pacific, and from the northern portions of Washington Territory to the table-lands of Mexico. Mr. Ridgway found this species abundant, during the summer months, in all the fertile wooded districts along the entire route of the survey. At Sacramento it was common in the willow copses, and was observed in the greatest numbers, in May, in the rich valley of the Truckee, in company with Bullock’s Oriole, the Louisiana Tanager, and other species, feeding upon the buds of the “grease-wood.” It principally inhabits the willows along the rivers, and the shrubbery skirting the streams of the mountain cañons. In its manners and notes Mr. Ridgway regards this bird as an exact counterpart of the eastern species, the _Hedymeles ludovicianus_, its song being by no means superior. The peculiar and very odd _click_ of the _ludovicianus_ is said to be equally characteristic of this bird. Mr. Ridgway met with its nests in willows, about ten feet from the ground. He had evidence that the male bird assists the female in the duties of incubation. This bird, though a common summer resident in the Great Salt Lake Valley, had all migrated, according to Mr. Allen, by the 1st of September. It is well known there as the Peabird, from its fondness for green peas, of which it is very destructive.