Bill long or of moderate length, straight, stout, angulate, tapering, compressed toward the tip, which is generally wedge-shaped and abrupt; mandibles nearly equal, outline of the upper slightly convex, the ridge narrow, sides sloping, with a lateral ridge, edges straight; lower with the angle short and narrow, the dorsal line nearly straight, the ridge narrow, the sides with a faint ridge. Nostrils basal, elliptical or oblong, concealed by reversed bristly feathers. Head of moderate size, oblong; neck of moderate length; body stout. Legs short; tarsus short, moderately stout, anteriorly scutellate, scaly behind; toes usually four, first short, rudimentary, or sometimes wanting, fourth very long and reversed, equalling or exceeding the third. Claws large, strong, much curved, much compressed, very acute. Plumage soft, blended, rather compact on the back; wings of moderate length or long; with the first quill very small, the third, fourth, and fifth longest. Tail of moderate length, much rounded or cuneate, of twelve feathers, of which the lateral are extremely small, and placed above the next, the rest, but especially the three middle pairs, with the shafts exceedingly large and strong, the webs narrowed toward the end, with their filaments deflected and stiff, the tip pointed or emarginate from being worn. Tongue slender, with the tip horny and furnished with reversed prickles or bristles, capable of being protruded to a great length by the elongation of the hyoid bones, which curve over the head to between the right eye and nostril, or even extend round a great part of that eye. Œsophagus of uniform width; proventriculus extremely large; stomach of moderate size, or rather small, broadly elliptical or roundish, moderately muscular; epithelium thin, dense, and longitudinally rugous; intestine of moderate length, rather wide; no cœca; cloaca very large, globular, or elliptical. Trachea simple, with a single pair of inferior laryngeal muscles. Nest a cavity dug in a tree; eggs from four to six, elliptical, white. The groups present characters which are so undecided, and exhibit such gradual approximations, that I think it better here to consider all our Woodpeckers as of one genus. GENUS I. PICUS, Linn. WOODPECKER. Character as above. * Bill straight, with the angles prominent. 256. 1. Picus imperialis, Gould. Imperial Woodpecker. Not figured. Glossy greenish-black; the elongated occipital crest scarlet; a triangular spot on the fore part of the back; the secondary quills, and the inner webs of most of the primaries, white; bill yellowish-white. Female similar, but without red on the head. Gould. _Male_, 24, wing 12. Rocky Mountains and North California. Picus imperialis, Gould. Proceed. of Com. Sc. and Corresp. of Zool. Soc. of Lond. part ii. p. 140. Imperial Woodpecker, Picus Imperialis, Aud. Orn. Biog. v. v. p. 313. 257. 2. Picus principalis, Linn. Ivory-billed Woodpecker.