It is an interesting fact, that, in this species, we find in the yellow a tendency to become more and more restricted as we pass westward. In adult spring males from the Atlantic States this color invades the cheeks, and even stains the lores and eyelids. In two adult spring males from Chicago it is confined within the maxillæ, the cheeks being clear ash, and the loral streak and orbital ring pure white; while in an adult male (autumnal, however) from the East Humboldt Mountains (Nevada, No. 53,354, U. S. Geol. Expl., 40th par.) the yellow is restricted to a medial strip, even the sides of the throat being ashy; the ash invades the back too, almost to the rump, while in Eastern specimens it extends no farther back than the nape. A male (No. 10,656, J. Xantus) from Fort Tejon, Cal., is much like the Nevada specimen, though the peculiar features of the remote Western form are less exaggerated; it is about intermediate between the other specimen and the specimens from Chicago. As there is not, unfortunately, a sufficiently large series of these birds before us, we cannot say to what extent these variations with longitude are constant. HABITS. The Nashville Warbler appears to be a species of somewhat irregular occurrence; at one time it will be rather abundant, though never very numerous, and at another time comparatively rare. For a long while our older naturalists regarded it as a very rare species, and knew nothing as to its habits or distribution. Wilson, who first met with it in 1811, never found more than three specimens, which he procured near Nashville, Tenn. Audubon only met with three or four, and these he obtained in Louisiana and Kentucky. These and a few others in Titian Peale’s collection, supposed to have been obtained in Pennsylvania, were all he ever saw. Mr. Nuttall at first regarded it as very rare, and as a Southern species. In that writer’s later edition he speaks of it as a bird having a Northern distribution as far as Labrador. Dr. Richardson records the occurrence of a single straggler in the fur country. So far as known, it occurs as a migrant in all the States east of the Missouri, and is a summer resident north of the 40th parallel. It probably breeds in the high ground of Pennsylvania, though this fact is inferred rather than known. It breeds in Connecticut and Massachusetts, and in Maine in the vicinity of Calais, being more abundant there than anywhere else, as far as has been ascertained. Two individuals of this species have been taken in Greenland: one at Godthaab, in 1835; and the other at Fiskenæsset, August 31, 1840.