BIRDS—ERISMATURINAE—ERISMATURA RUBIDA. 
811 
Sub-Family ERISMATURINAE. 
The most prominent character of the Erismaturinae is found in the very rigid tail feathers 
with the much abbreviated coverts, which leave the greater portion of the tail exposed. There 
are peculiarities in the nail at the end of the hill in Erismatura not found in the other sub-families. 
ERISMATURA, Bo nap. 
O'xyura, Bonap. Syn. 1828. Type Anas rubida. Sufficiently distinct from Oxywrus.? Type Anas leucocephala, Scop. 
Erismatura, Bonap. Saggio, etc., 1832. 
Ch. —Bill broad, rather high at the base, much depressed, and bent upwards. Upper lateral angle of bill running back on 
the forehead some distance; farther than the lower edge of the bill. Nostrils reaching to the middle of the bill, rather small. 
Portion of nail seen from above very narrow and linear; bent abruptly downwards and backwards at the tip so as to be 
invisible from the upper surface. Tarsi very short, scarcely more than one-third the long feet. Tail very stiff; of 18 feathers. 
The coverts above and below very much abbreviated, so as to expose the greater part of the tail. The feathers narrow, 
linear. The shafts very large, and channelled on the under surface near the base. Wings very short, and incurved at the end. 
Of this genus there are several species belonging to America, although but one is well 
established as an inhabitant of the United States. Dr. Cabot, however, has recently announced 
the occurrence of the E. dominica on Lake Champlain. 
Comparative measurements of species. 
ERISMATURA RUBIDA, Bonap. 
Ruddy Duck. 
Anas rubida, Wilson, Am. Orn. VIII, 1814, 128, 130 ; pi. lxxxi. 
Anas ( Fuligula ) rubida, Bon. Obs. Wils. 1825, 268. 
Fuligula ( Oxyura ) rubida, Bon. Syn. 1828, 390. 
Fuligula (Gymnura ) rubida, Nuttall, Man. II, 1834, 426. 
Fuligula rubida, Sw. F. Bor. Am. II, 1831, 455.— Aud. Orn. Biog. IV, 1838, 326 ; pi. 343 .—Ib. Syn. 288 .—Ib. 
Birds Am. VI, 1843, 324 ; pi. 399. 
Erismatura rubida, Bonap. List, 1838.— Eyton, Mon. Anat. 1838, 171. 
Anas jamaicensis, “Lath.” —Oud, ed. Wilson, VIII, 1825, 138. 
Sp. Ch.—B ill grayish blue. Top of head and nape black. Sides of head below the eyes, with the chin, pure opaque white. 
Lower part of neck all round, and the entire upper parts, with upper portion of sides, chestnut red. Under parts generally 
lustrous grayish white, with an occasional brownish tinge ; crissum pure white ; wings brown, without speculum, finely and 
almost inappreciably sprinkled with gray ; tail nearly black. 
Female with the entire upper parts dark brown ; the back and wing coverts finely sprinkled with grayish. The under parts 
brownish white, tinged with greenish brown across the lower part of neck. The brown of the head comes down below the 
level of the eye, and there is an obscure dusky stripe parallel with its lower outline, from the commissure. 
Length, 16.00 ; wing, 5.80; tarsus, 1.26; commissure, 1.80. 
Flab. —Whole of North America. Abundant throughout the interior. 
The continuity of tlie white of the under parts is interrupted by the occasional appearance 
of the basal brown of the feathers, owing to the shortness of the white tip, which thus gives rise 
to the appearance of dusky transverse bands. 
