146 U. S. P. R R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
Family CAPRIMULGIDA E - The Goat-suckers. 
Sub-Family CAPRIMULGINAE. 
Cu.—Bill very short, triangular, the culmen less than one-sixth the gape. The anterior toes united at the base by a 
membrane The inner anterior toe with three joints, the others with four; all with distinct scutellae above. The toe much 
elongated, its middle claw pectinated on the inner edge. Hind toe directed a little more than half forwards. Tarsi partly 
feathered superiorly. The bill more or less bristled ; the nostrils separated, rather nearer the commissure than the culmen. 
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mage soft, lax, and owl-like. 
The Caprimulgidae have quite a close resemblance to the owls in the color and texture of the 
plumage, as well as in the broad head, although, of course, readily distinguishable by unmis- 
takable characters. The closest relationships are to the Cypselidae. The primary quills are 
ten in number, the secondaries eleven or twelve. The latter are much longer than in the 
Cypselidae, covering more than half the primaries. The middle toe is much longer than in the 
Cypselidae, and its claw is usually provided with a comb-like edge on one side. The anterior 
toes are united by a membrane, the inner and middle usually more so than the middle and outer. 
The inner toe is small, and the outer is usually so, having generaliy only four joints instead of 
the normal five. The tarsi are covered with short scales anteriorly, their upper portion 
generally clothed with feathers. 
The Caprimulgidae are divided into two sub-families, the Steatorninae and Caprimulginae, the 
former having the inner edge of the middle anterior claw expanded, but not pectinated. A 
third sub-family Podagerinae is sometimes added. The Caprimulginae alone are represented in 
the United States, and by two genera, Antrostomus and Chordeiles, which may readily be 
distinguished as follows : 
ANTROSToMUS.—Bill with conspicuous bristles. Wings short, rounded; tail broad, graduated ; 
plumage very lax. 
CuyorDEILES.—Bill without bristles; wings very long and pointed; tail narrow, forked ; 
plumage compact. 
ANTROSTOMUS, Gould. 
Antrostomus, Gout, Icones Avium, 1838, (Agassiz. ) 
Cu.—Bill remarkably small, with tubular nostrils, and the gape with long stiff, sometimes pectinated, bristles. Wings 
long, somewhat rounded, second quill longest, the primaries emarginated. ail rounded. Plumage loose and soft. 
The present genus embraces the North American analogues of the European goat-suckers— 
namely, the chuck-will’s widow and the two species of whippoorwill. Of these, the former, or 
A. carolinensis, is much the largest, with the long stiff bristles of the bill provided with lateral 
filaments ; these are wanting in the A. vociferus and A. nuttalli. In vociferus, which is much. 
the larger of the two last, the throat has a narrow white collar, and the lower terminal half of the 
tail is white; the head longitudinally streaked. In nuttalli the throat has a large white patch ; 
the under surface of the tail a small one, and the crown is banded transversely, not longitudinally. 
