S66 BlfiOS OF ILLINOIS. 



FAiriLT CAPRIMULGID-ffi.— The Goatsuckers. 



Chae. Bill very short; the gape enormously long and wide, opening to benpath or 

 behind the eyes. Culmen variable. Toes connected at base by a movable slcin; second- 

 aries lengthened; plumage soft, sometimes very full and loose, as in the Owls. 



The above brief diagnosis is sufficient to distinguish this family 

 from all others in North America, especially when taken in con- 

 nection with that given on page 358. 



The North America genera are distinguished by the following 

 characters : 



A. Gape with conspicuous bristles; tail even or rounded. 



o. Tarsus feathered in front almost to the toes, and shorter than the middle toe. 

 First quill longer than the fourth. 



1. Antrostomus, Tail rounded, shorter than the wing. 



h. Tarsus entirely nalied in front, and longer than the middle toe. First quill shorter 

 than the fourth. 



2. Phalaenoptilus. Tail even and much shorter than the wing. Plumage with a 

 peculiarly soft, velvety surface. Sexes with the tail not differently marked. 



3. Nyotidromns. Tail rounded, long as the wing. Sexes with the tail very differ- 

 ently marked. 



B. Gape without conspicuous bristles; tail emarginated or slightly forked. 



4. Chordeiles. 



Genus ANTROSTOMUS Gould. 



Antrostomus Gould. Icones Avium, 1838. Type, Caprimulgus carolinensis Gm. 



Geh. Chab. Bill very small, with tubular nostrils, and the gape with long, stiff, some- 

 times pectinated bristles projecting beyond the end of the bill. Tarsi shorter than mid- 

 dle toe, chiefly feathered. Tail broad, rounded; wings broad and rounded; first quill 

 shorter than third, but longer than the fourth; plumage soft and lax. Habits nocturnal. 



The two North American species, both of which occur in Illinois, 

 may be distinguished as follows : 



A. Bictal bristles with lateral filaments. Wing more than 8 inches. 



1. A. carolinensis, Male. Terminal half or third of inner webs of three outer tnil- 

 feathers buffy whitish or ochraceous. Female. Outer tail-feathers without light 

 tips. 



B. Kictal bristles without lateral filaments. Wing less than 7 inches. 



2. A. Tocifems. Male. Tail-feathers (except middle pair) with terminal third of both 

 webs white. Female. Tail-leathers without white tips. 



