FAMILY RHINOCRYPTIDAE 255 



about, the tail is held at an angle above the back, from which they 

 have received the common name of tapaculo. 



The little known of the various kinds in life indicates that some 

 place their nests in holes dug in the ground. Others use cavities or 

 crevices beneath loose bark on the bases of trees. The eggs, where 

 known, number two or three, are large for the size of the parent, and 

 are white without markings. 



The genus Scytalopus, the only one found outside South America, 

 with 9 species and more than 20 geographic races, ranges north from 

 the Falkland Islands. Tierra del Fuego, and southern Chile through 

 the Andes to the mountains of Costa Rica. Three species are repre- 

 sented in Panama. 



KEY TO SPECIES OF RHINOCRYPTIDAE ( ADULTS ) 



1. Forecrown light or dark gray. 



Silvery fronted tapaculo, Scytalopus argentijrons. p. 255 

 Entire crown black, or blackish brown 2 



2. A well-marked grayish white superciliary line. 



Pale-throated tapaculo, Scytalopus panamcnsis, p. 259 

 Side of head and crown plain, without a superciliary line. 



Narino tapaculo, Scytalopus vicinior, p. 260 



Immature birds in all three species are light to dark buff, spotted 

 and barred with dusky. Specific dififerences in this stage are not 

 clearly indicated in the limited series of specimens seen. 



SCYTALOPUS ARGENTIFRONS Ridgway: Silvery fronted 

 Tapaculo, Tapaculo Plateado 



Figure 22 



Small ; wrenlike in form and actions ; adult with gray center of 

 crown. 



Description. — Length 115-120 mm. Bill very short (definitely 

 shorter than the head), the line of the culmen slightly depressed near 

 center. Adult male, crown silvery gray, extending posteriorly on either 

 side as a broad superciliary line; forehead, side of head (including 

 area surrounding eyes), back, scapulars, wings, and tail sooty black; 

 rump and upper tail coverts chocolate-brown ; under surface from 

 chin to abdomen slate color to blackish slate, blacker on the sides; 

 flanks and under tail coverts deep russet-brown, barred narrowly 

 with black. 



Adult female, with the gray of the crown and superciliary darker, 

 reduced in extent, in some nearly absent ; feathers of dorsal surface 



