Head of moderate size, ovate, narrowed anteriorly, convex above. Eyes of moderate size. Neck rather short. Body rather slender. Wings very long. Feet of moderate length, rather strong; tibia bare below for a short space, covered behind with narrow scutella; tarsus compressed, anteriorly covered with numerous scutella and three inferior series of transverse scales, laterally with oblong scales, posteriorly with oblique scutella. Toes slender, with numerous scutella; first extremely small, second considerably shorter than fourth, third longest; anterior toes connected by reticulated webs, of which the anterior margins are deeply concave, the outer and inner slightly marginate. Claws small, compressed, moderately arched, rather obtuse, that of middle toe with an expanded inner edge. Plumage full, close, soft, blended. Wings very long and pointed; primaries tapering and rounded, first longest, second very little shorter, the rest rapidly graduated; secondaries obliquely pointed, the rounded extremity extending beyond the tip of the shaft, which is exterior to it, the inner feathers more elongated. Tail of moderate length, almost even, the middle feathers slightly longer. Bill black, inside of mouth vermilion. Iris reddish hazel. Feet orange, slightly tinged with vermilion; claws dusky brown. Head and upper part of neck all round, greyish-black, that colour extending half an inch lower on the throat than on the occiput. A white band divided by a narrow black line margining the eye behind; the remaining part of the neck white; back, scapulars and wings, light greyish-blue. The anterior ridge of the wing, alula, smaller coverts on the carpal margin, four outer primary coverts, shaft and inner web of the outer primary, both webs of second, inner webs of third and fourth white; of which colour also are the rump, tail, and all the lower parts. Outer web of first quill, excepting a small portion towards the end, its tip to the length of half an inch, black, as are the ends of the next six, which however have a small tip of white, the black on some of them about an inch long, and running along the inner edge to a considerable extent. Length to end of tail 14-1/8 inches, to end of wings 15-5/8, to end of claws 13-1/8; extent of wings 32-1/4; wing from flexure 10-3/4; tail 4-2/12; bill along the ridge 1-4/12, along the edge of lower mandible 1-10/12; tarsus 1-3/12; hind toe and claw (3-1/4)/12; middle toe 1-3/12; its claw (3-1/4)/12, outer toe 1-(1/3)/12, its claw (2-1/4)/12; inner toe 11/12, its claw (2-1/2)/12. Weight 6-1/2 oz. Adult Female. Plate CCCXXIV. Fig. 2. The female is somewhat smaller, and resembles the male, but has the head and upper part of the neck umber brown. Young in December. Plate CCCXXIV. Fig. 3.