350 BULLETIlSr 50, UNITED STATES ISATIONAL MUSEUM. 



Medium t^ized, rather small, or large Frinoillida? with short, rounded 

 wing-, rather long- (nearly equal to or longer than wing), rounded or 

 double-rounded tail, and conspicuousl}^ streaked brownish plumage 

 (unstreaked l)elow only in adult of J/. <jt'<>)u//(nia). 



Bill variable in proportionate length and depth, but exposed oulmen 

 never much more than half as long as tarsus and basal depth never less 

 than two-thirds the length of gonys nor more than length of the latter; 

 eulmen gentl}' convex for most of its extent, straight or faintly 

 depressed in middle or post-median portion; gonys straight or faintly 

 convex, nearly or quite equal to length of maxilla from nostril; max- 

 illary tomium with subterminal notch oljsolete or wanting, verv faintly 

 concave anteriorly and convex posteriorly, the slightly deflected basal 

 portion nearly or quite concealed by rictal feathers; mandibular tom- 

 ium straight to the sabbasal angle. Nostril small, nearly circular, 

 partly concealed l)y bristly plumelets. Wing short (about two and 

 two-thirds to barely more than three times as long as tar.sus), rounded 

 (eighth to fifth primaries longest, ninth shorter than fourth); prima- 

 ries exceeding secondaries by much less than length of tarsus (usually 

 by not more than length of exposed eulmen). Tail equal to or slightly 

 longer than Aving (clncrta), decidedly shorter than wing {llncolni) or 

 intermediate, the rectrices rather narrow, obtuselj^ rounded at tips 

 (almost acuminate in georgiaiui)^ less than half overlaid hy upper 

 coverts. Tarsus about equal to middle toe with claw or a little longer, 

 its scutella fairl}' distinct; lateral claws not reaching to base of middle 

 claw; hallux a])out equal to inner toe, its claw nearly as long as the 

 digit. 



Coloration. — Above grayish, brownish, olive, or rusty, more or less 

 distinctly streaked, especially on the l)ack, with darker; top of head 

 brownish, streaked with darker, and divided medialh' b}" a more or 

 less distinct grayish stripe, or else chestnut becoming black on forehead; 

 wings and tail brownish (usually more or less rusty) the former without 

 distinct light-colored bands; ear-coverts and superciliar}^ stripe gray- 

 ish, separated by a brownish or dusky postocular streak; a whitish, 

 ligfit grayish, or buft'y malar stripe, ])ordered ])elow Ijv a more or less 

 distinct brown or dusky streak alongside of throat; lower parts mainl^^ 

 whitish, the chest and sides usuall}' streaked with rust}-^, brown, or 

 dusky. Young similar to adults, but markings less sharph' delined 

 and colors more blended. 



The type-species of this genus is a l)ird of very extensive geographic 

 range, breeding throughout the temperate parts of the North American 

 continent, including the plateau of Mexico. No other bird of the 

 Nearctic Region has proven so sensitive to influences of physical 

 environment, and as a result of this plasticity of organization it has 

 become divided into a large number of geographic forms, some of 

 extensive others of very circumscribed range, the area of distribution 



