632 U. Ss. BP. R. R, EXP, AND SURVEYS—ZOOLOGY—-GENERAL REPORT. 
LAGOPUS, Vieillot. 
Lagopus, Vierttor, Analyse, 1816. Type Tetrao lagopus, L. 
Cu.—Nasal groove densely clothed with feathers. Tail of sixteen or eighteen feathers. Legs closely feathered to the claws. 
Species snow white in winter. 
The ptarmigans inhabit the northern regions of both hemispheres, and with the arctic fox 
and hares, the lemmings, and a few other species, characterize the Arctic zone. They are of 
rare occurrence within the limits of the United States, though further north they become 
abundant. The species all become more white in winter, but in summer they are varied with 
brown, black, and gray, most of the wing remaining white. There is, generally, consid- 
erable difference between the male and female, the former having the mottling finer and the 
colors more blended ; and in some species having a peculiar black stripe through the eye. 
As in most grouse there is a naked stripe above the eye, which is generally colored red, and 
exhibiting a series of fringed processes. 
There is some uncertainty as to the name proper to be used for this genus. Gray sets aside 
Lagopus of Vieillot, 1816, as not the same with Lagopus of Brisson, 1760. If, however, Bris- 
son be no authority for species, he may not be for genera; and, his name being disregarded, 
Vieillot’s Lagopus would retain its position. 
The study of the American ptarmigans is rendered very difficult by the extreme difficulty of 
procuring specimens in summer plumage, and with accurate indications of sex. European 
naturalists, many of whom live among the ptarmigan, have not yet come to a positive conclusion 
as to the number of species to be counted, whether two, three or more, while the investigation 
of our own species is complicated by the extreme rarity of good skins in collections, the imper- 
fect notice of locality and sex, and the remoteness from the localities where these birds abound. 
In the collection before me, made up chiefly of specimens kindly presented to the Smithsonian 
Institution by Mr. John Gould, and of others received from Mr. Audubon, some of them appa- 
rently types of his descriptions, are various stages of plumage and structure, which might throw 
considerable light on the subject, but for the unfortunate uncertainty, in some cases, as to 
whether they are European or American. There are in this series certainly three species, and 
indications of a fourth, possibly of a fifth, but Ido not venture here to do more than indicate 
three, I find none which correspond with what Mr. Audubon has called Z. americanus. 
The specimens vary considerably in the precise character of bill, which is more or less convex, 
but there is a decided difference in the average of the willow and the rock grouse. The size of 
the two species differs also. Both have the tail feathers black, and differing in this respect 
from the L. lewcurus, in which they are white. 
I give the accompanying descriptions of North American ptarmigans, without much assurance of 
even approximate accuracy, in respect to the number, characters, and synonymy of the 
species. Their chief characters are expressed in the following synopsis : 
Tail feathers black. 
Bill stout, convex, broad at tip; the distance from the nasal groove to the tip of bill equal to 
or less than the greatest height of both mandibles together. No black loral stripe in the 
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