Bill depressed, triangular, compressed at the end, upper mandible notched, lower with the point slightly ascending. Head rather large, depressed; neck short; body rather slender. Feet generally short; tarsus short, slender, with very broad scutella; toes four, free; the hind toe not proportionally large; claws arched, compressed, acute. Plumage soft and blended. Wings long, with the first quill generally long, the outer three longest. Tail various. Tongue flattened, sagittate, bristly at the tip; œsophagus wide, without crop; stomach elliptical, moderately muscular, with the lateral muscles distinct, the epithelium thin, dense, longitudinally rugous; intestine short; cœca extremely small; cloaca globular. Trachea simple; inferior laryngeal muscles, forming on each side a large pad, but not divisible into several portions as in the singing birds. Nests regularly formed, cup-shaped. Eggs from four to six. GENUS I. MILVULUS, Swains. SWALLOW-TAIL. Bill moderate, rather stout, straight, broad at the base, gradually compressed toward the end; upper mandible with the dorsal outline a little convex, the edges sharp and nearly perpendicular, with a very small notch close to the small deflected tip; lower mandible with the ridge very broad at the base, the sides rounded, the tip minute and ascending. Nostrils basal, broadly elliptical. Head rather large, depressed; neck short; body rather slender. Feet rather short; tarsus short, slender, compressed, with very broad scutella, some of which almost meet behind; toes free, the hind toe not proportionally larger, all scutellate above; claws of moderate size, arched, compressed, acute. Plumage soft and blended. Wings long, second quill longest, first almost as long as third, the three outer abruptly notched near the attenuated tip. Tail extremely elongated and forked, the middle feathers being of ordinary length, the lateral longest. 52. 1. Milvulus Tyrannus, Linn. Prairie Swallow-tail.--Fork-tailed Flycatcher. Plate CLXVIII. Male. Tail more than twice the length of the body; upper part of head and cheeks deep black, the feathers of the crown bright yellow at the base; back ash-grey, rump bluish-black; wings and tail brownish-black, the lateral feathers of the latter with the outer web white for half its length; lower parts white. _Male_, 14-1/4, 14. In Louisiana, very rare. Accidental in New Jersey. Fork-tailed Flycatcher, Muscicapa Savana, Bonap. Amer. Orn. v. i. p. 1. Muscicapa Savana, Bonap. Syn. p. 67. Fork-tailed Flycatcher, Muscicapa Savana, Nutt. Man. v. i. p. 274. Forked-tailed Flycatcher, Muscicapa Savana, Aud. Orn. Biog. v. ii. p. 387. 53. 2. Milvulus forficatus, Gmel. Red-shouldered Swallow-tail.--Swallow-tailed Flycatcher. Plate CCCLIX. Fig. 3. Male.