596 BULLJCTIN 50, UNITED STATES NATIONAL MUSEUM. 



Bill .shorter than head, very slender, .straight-subidate, its basal 

 depth and width about equal; exposed cuhnen shorter than middle 

 toe without claw, straight to near extreme tip, where very slightly 

 decurved; gon3^s decidedly shorter than distance from nostril to tip of 

 maxilla, straight; maxillary tomium nearl}^ straight, without trace 

 of subterminal notch. Nostril longitudinal, narrowly cuneate or 

 guttate (pointed anteriorly), overhung by a distinct excurrent corneous 

 operculum, posteriorly in contact with feathering of latero-frontal 

 antiffi. Rictal bristles obsolete. Wing short, rounded; seventh and 

 sixth, or seventh, sixth, and lifth, primaries longest, the eighth equal 

 to or slightly shorter than tifth; ninth equal to lirst or second, about 

 twice as long as tenth or slightly less. Tail two-thirds as long as 

 wing, much rounded, the rectrices relativel}' narrow, with rounded 

 tip. Tarsus longer than middle toe with claw, decidedly more than 

 one-third as long as wing, the acrotarsium distim^tly scutellate, the 

 planta tarsi booted; outer too (without claw) reaching to slightly 

 beyond second (subterminal) joint of middle toe, its claw falling short 

 of base of middle (;law; inner toe (without claw) reaching to, but not 

 bej^ond, subterminal joint of middle toe; hallux (without claw) as 

 long as outer toe (without claw) but much stouter, its claw shorter 

 than the digit; basal phalanx of middle toe adherent to outer toe for 

 nearh' its entire length, to inner toe for half its length, or a little 

 more. 



Coloi'atlon. — A])ove brown, more or less ))arred (sometimes narrowly 

 and indistinctly) with dusky, at least on wrings and tail; narrow super- 

 ciliar}^ stripe and under parts pale brownish, posteriorly more or less 

 barred (irregularly) with dusky. 



Nidification. — Nest built among roots of upturned trees, in cavities 

 of old logs, stumps, etc. , among rocks, in thickets, or in lower part of 

 dense evergreens, occasionally in buildings; domed or oven-shaped, 

 with entrance in ohe side; composed of various materials, usually 

 selected to correspond with its surroundings (externally of green 

 moss, if in mossy places, etc.). Eggs white, usually speckled with 

 reddish brown. 



Range. — Colder portions of northern hemisphere. (Several species.) 



KEY TO THE SPECIES AND SUBSPECIES OP OLBIORCHILUS. 



o. Smaller (wing 40-50, averaging much less than 50, exposed culmen 10-13). 



h. Bill smaller (exposed culmen 10-12.5, averaging less than 12) ; coloration darker. 

 c. Duller in color; bill stouter. (Eastern North America. ) 



Olbiorchilus hiemalis hiemalis (p. 597) 

 cc. Brighter and more rufescent in color; bill more slender. ( Western United 

 States and British Columbia; southern Alaska. ) 



Olbiorchilus hiemalis pacificus (p. 600) 

 hh. Bill larger (exposed culmen 12-13, averaging more than 12) ; cdloration paler. 



(Kadiak Island, Alaska.) Olbiorchilus hiemalis helleri (p. 602) 



aa. liarger (wing 48.5-55, averaging more than 50, exposed culmen 13-15), 



