462 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



familiai'ift Linnseus) ranges nearly throughout the extensive area indi- 

 cated, and being therefore subjected to very diverse environments has 

 become differentiated into a considerable number of subspecific forms, 

 of which the Nearctic Region alone possesses at least six. 



Genus CERTHIA Linnasus. 



Ceriida Linn^us, Syst. Nat., ed. 10, i, 1758, 118. (Type, by elimination, 



C. familiaris Linnaeus. ) 

 Certhius (emendation) Olphe-Galliaed, Orn. Eur. Occ., 1888, xxiii, 41. 



Small Certhiidse with the tail nearly equal to or slightly longer than 

 wing, graduated, the rectrices with rigid and acuminate tips, and with 

 the plumage of upper parts conspicuously streaked. 



Bill variable as to relative length and degree of curvature, some- 

 times decidedlj' shorter than head and nearly straight, sometimes 

 much longer than head and strongly curved, always much compressed; 

 gonys more or less concave, sometimes very decidedly so, occasionally 

 (in shorter billed examples) nearly straight, shorter than distance 

 from nostril to tip of maxilla; maxillary tomium without trace of 

 subterminal notch. Nostril entirely exposed, overhung by a broad 

 operculum, which auteriorly does not extend to anterior end of nasal 

 fossa. Rictal bristles obsolete. Wing moderate, rounded; eighth, 

 seventh, and sixth, or eighth to fifth, primaries longest, the ninth not 

 longer than fourth, sometimes not longer than third, the tenth less 

 than half as long as ninth. Tail nearly or quite as long as wing, 

 sometimes slightly longer, graduated, the rectrices with rigid and 

 acuminate tips. Tarsus decidedly longer than middle toe without 

 claw but shorter than middle toe with claw, the acrotarsium distinctly 

 scutellate; outer toe much longer than inner toe, the former reach- 

 ing beyond middle of subterminal phalanx of middle toe, the latter 

 scarceh' reaching to second (middle) joint of middle toe; hallux 

 intermediate in length between outer and inner toes; basal phalanx 

 of middle toe adherent for entire length to both lateral toes; claws 

 long and strongly curved, that of the hallux equal to or longer than 

 the digit. 



Coloration. — Above brownish, conspicuously streaked with darker 

 and paler, the wings dusky varied with pale grayish or brownish, the 

 inner webs of remiges (except outermost primaries) crossed by a broad 

 band of buff or whitish; under parts plain white, pale gray, or pale 

 brown, the posterior portions more or less tinged with tawny or 

 rusty. 



Nidification. — Nest in cavities of trees or stumps (usually behind 

 stripsof loosened bark), of soft felted materials; eggs numerous (5 to 9), 

 white, whitish speckled with reddish brown. 



