Basal joint of middle toe shorter than that of the inner toe, united to the outer for about two thirds, to the inner for about one half, its length. Tarsus longer than middle toe and claw. Gonys more than half the length of the under jaw. Bill very weak and slender, little decurved or notched at tip. Very small,—under six inches long. (Tarsi booted in Regulus, distinctly scutellate in Polioptila.) … Sylviidæ.
ff. Basal joint of middle toe quite free from the inner, and not united with the outer more than half-way.
Nostrils linear, low. No bristles or bristly points whatever about the mouth. Wings short, rounded, concavo-convex. Tail very short, nearly concealed by its coverts. Tarsi booted … Cinclidæ.
Nostrils oval. Bristles or bristly points about the mouth. Wings very long and pointed, reaching, when folded, beyond the middle of the short, square, or emarginate tail, and one and a half times or more
the length of the latter; tip formed by second, third, and fourth quills; outer secondary reaching only about two thirds way to end of longest primary; spurious quill very short. Tarsi booted … Saxicolidæ.
Nostrils oval. Bristles or bristly points about the mouth. Wings moderate, not reaching, when folded, beyond the middle of the tail, and not over one and a third times as long as the latter; tip formed by third to sixth quill; outer secondary reaching in closed wing three fourths or more the length of the longest primary. Spurious quill longer, sometimes one half the second. Tarsi scutellate in Miminæ, booted in Turdinæ … Turdidæ.
aa. Outside of tarsus covered with two series of scutella,—one lapping entirely around in front, the other entirely around behind, and meeting at a groove on the inside; hind edge blunt. First primary spurious or apparently wanting. Hind claw much lengthened, scarcely curved. Nostrils with antrorse bristly feathers. Bill conico-elongate … Alaudidæ.
B. Clamatores. Outside of tarsus covered with a series of plates variously arranged, lapping entirely around in front and behind, to meet at a groove on the inner side.
First primary lengthened, often longest, at least over two thirds as long as the longest. Bill broad at the base, much depressed, tapering to a fine point, which is abruptly decurved; culmen rounded or flattened; gonys flattened; commissure straight, or nearly so, to the tip. Nostrils small, circular, basal; overhung, but not concealed by bristles. Mouth capacious, with broad and deeply fissured rictus, beset with numerous long strong bristles. Feet small, weak. Tail of twelve feathers … Tyrannidæ.
Analysis of the Families of PICARIÆ.