470 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



and lores stiff and erect; tibial feathers much developed, completely 

 covering tibio-tarsal joint; coloration uniform dusky grayish with 

 black pileum and conspicuous yellow thighs. 



Bill rather slender, the maxilla hardly as deep as the mandible; depth 

 of bill through base about two-thirds as long as gonys, little if any 

 greater than basal width; culmen strongly ridged, very faintly convex 

 except terminally, where more decidedly decurved; gonys nearly equal 

 to length of maxilla from nostril, faintly convex, with rather promi- 

 nent basal angle; maxillary tomium with distinct subterminal notch, 

 thence very faintly concave to the gently deflected basal portion; 

 mandibular tomium straight to the subbasal angle, the latter very 

 faintly toothed, the basal deflection comparatively slight. Nostril 

 wholly exposed, longitudinal, with broad superior membrane. Rictal 

 bristles minute, scarcely obvious; feathers of forehead and lores erect, 

 rather stiff. Wing moderate (a little less than three times as long as 

 tarsus), rounded (seventh to fifth primaries longest, ninth shorter than 

 secondaries); primaries exceeding secondaries by less than length of 

 exposed culmen. Tail about equal to or a little longer than wing, 

 much rounded, its feathers broad, with semi-decomposed webs and 

 acuminate tips. Tarsus rather long, much exceeding middle toe with 

 claw, its scutella distinct; lateral claws falling short of base of middle 

 claw; hallux about equal to outer toe, its claw shorter than the digit. 

 Tibial feathers long, forming a conspicuous fluffy tuft surrounding 

 and quite covering the tibio-tarsal joint. 



Coloration. — Adults uniform dull slate color, darker on wings and 

 tail; pileum black; tibial tufts clear lemon yellow, in conspicuous 

 contrast. 



Bcmge. — Highlands of Costa Rica and Chiriqui. (Monotypic.) 



PSELLIOPHORUS TIBIALIS (Lawrence). 

 YELLOW-THIGHED SPARROW, 



Admits {sexes alike). — Pileum uniform black; rest of upper parts 

 plain sooty slate, darker (nearly black) on wings and tail; under parts 

 plain dull slate or mouse gray, darkening to blackish on chin and 

 throat, the breast sometimes tinged with yellow, producing an oliva- 

 ceous tint; thighs clear lemon yellow, in conspicuous contrast; bill 

 black; legs and feet brownish. 



Young. — Similar to adults, but without yellow on thighs, and colora- 

 tion in general duller. 



Adult maZe.— Length (skins), 182.88; wing, 76.96; tail, 85.09; ex- 

 posed culmen, 14.73; depth of bill at base, 7.11; tarsus, 36,67; middle 

 toe, 16.51.^ 



^ One specimen. 



