BIRDS OF NORTH AND MIDDLE AMERICA. 491 



exceedingly difficult to distinguish from their immediate surround- 

 ings of stony or sandy ground, dry leaves or grass, or branches of 

 trees. None of the species are known to build a nest, the eggs (also, 

 as a rule, protectively colored) being deposited on the gi'ound, or 

 other plain surface. 



They are chiefly msectivorous, though some of the larger species 

 are known to swallow, entire, small birds. Many of the species are 

 noted for peculiar cries, the whip-poor-will and chuck-will's-widow 

 of the United States bemg well-known examples. The name "goat- 

 sucker" is derived from an old-time superstition (perhaps not yet 

 altogether obsolete) that the connnon European species subsisted 

 by milkmg goats — a notion which doubtless arose from seemg the 

 birds flyuig close about the goats at night, or during the twUight, 

 but in reality capturmg the flies and other insects which infested the 

 animals. 



The family is found nearly throughout warmer portions of the 

 world, and is very numerous in species, about fifty, referable to four- 

 teen genera, occurring in America. 



KEY TO THE GENERA OF CAPRIMULGID^. 



a. Palate schizognathous; rictal bristles very large and conspicuous (twice as long 



as bill or longer); inframandibular region sparsely feathered ;« lower cervical 



pteryla without any inner branch or tooth; « maxilla without any lateral channel. 



( Caprimulginse.. ) 



h. Wing normal in both sexes (not more than two primaries eqtial in length). 



r. Bill very strong, very broad basally, its width at frontal feathering greater than 



its length from same point, the expanded basal portion with lateral outlines 



distinctly convex; nasal tubes semi-erect, stalk-like, the small nostril in 



the extremity and opening upward; legs and feet relatively large and stout. 



Siphonorhis (p. 495). 

 cc. Bill weak, not very broad basally, its width at frontal feathering much less 

 than its length from same point, the slightly or moderately widened basal 

 portion with lateral outlines not distinctly if at all convex; nasal tubes 

 shorter, less erect, the larger nostrils opening laterally or anteriorly; legs 

 and feet relatively small and weak. 

 d. Feathers of chest not specially developed, but uniform in length, etc., with 

 those of breast. 

 e. Tarsus with at least upper third feathered (except behind). 



/. Tail with some of the rectrices more or less conspicuously elongated. 

 g. Tail excessively simply forked, the lateral rectrices several times 

 longer than middle pair, the latter shortest. 



Macropsalis (extralimital).& 



« These characters have been verified only for the genera Antrostomus, Caprimul- 

 gus, Nyctidrovius, and Phalsenoptilus, and require confirmation for the other genera. 

 (See Hubert Lyman Clark, Proc. U. S. Nat. Mus., xvii, 1895, 553-557.) 



b Macropsalis Sclater, Proc. Zool. Soc. Lond., 1866, 143. (Type, Caprimulgus 

 forcipatus Nitzsch.= Hydropsalis creagra Bonaparte.) 



Colombia to Venezuela, Peru, Bolivia, and southern Brazil. (Four species.) 



