Pipilo erythrophthalmus. After a careful study of the very large collection of Black-headed Pipilos (leaving for the present the consideration of those with olive-green bodies) in the Smithsonian Museum, we have come finally to the conclusion that all the species described as having the scapulars and wing-coverts spotted with white—as _arcticus_, _oregonus_, and _megalonyx_, and even including the differently colored _P. maculatus_ of Mexico—are probably only geographical races of one species, representing in the trans-Missouri region the _P. erythrophthalmus_ of the eastern division of the continent. It is true that specimens may be selected of the four races capable of accurate definition, but the transition from one to the other is so gradual that a considerable percentage of the collection can scarcely be assigned satisfactorily; and even if this were possible, the differences after all are only such as are caused by a slight change in the proportion of black, and the varying development of feet and wings. Taking _maculatus_ as it occurs in the central portion of its wide field of distribution, with wing-spots of average size, we find these spots slightly bordered, or at least often, with black, and the primaries edged externally with white only towards the end. The exterior web of lateral tail-feather is edged mostly with white; the terminal white patches of outer feather about an inch long; that of inner web usually separated from the outer by a black shaft-streak. In more northern specimens the legs are more dusky than usual. The tail is variable, but longer generally than in the other races. The claws are enormously large in many, but not in all specimens, varying considerably; and the fourth primary is usually longest, the first equal to or shorter than the secondaries. This is the race described as _P. megalonyx_, and characterizes the Middle Province, between the Sierra Nevada of California and the eastern Rocky Mountains, or the great interior basin of the continent; it occurs also near the head of the Rio Grande. On the Pacific slope of California, as we proceed westward, we find a change in the species, the divergence increasing still more as we proceed northward, until in Oregon and Washington the extreme of range and alteration is seen in _P. oregonus_. Here the claws are much smaller, the white markings restricted in extent so as to form quite small spots bordered externally by black; the spots on the inner webs of tail much smaller, and even bordered along the shaft with black, and the outer web of the lateral entirely black, or with only a faint white edging. The concealed white of the head and neck has disappeared also.