■112 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Bill small and compressed, not more than half as long as head; 

 exposed culmen shorter than middle toe without claw, distinctly, 

 almost sharply, ridged, strongly curved from near base, the tip of 

 maxilla minutely and not distinctly uncinate ; gonys much longer than 

 mandibular rami, nearly straight ; maxillary tomium more or less con- 

 cave, minutely and not very distinctly notched subterminally ; width 

 of bill at frontal antife equal to about half the length of exposed cul- 

 men, and little if any greater than its depth at same point. Nostril 

 small, roundish, near center of nasal fossae, entirely surrounded by 

 membrane. Rictal bristles obvious on close inspection, but very 

 small ; feathers of chin and frontal antiiP with minute bristly points. 

 Wing moderate, with longest primaries exceeding secondaries by 

 about the length of exposed culmen, or considerably less; ninth, 

 eighth, or seventh, eighth, and ninth, primaries longest and nearly 

 equal, the tenth (outermost) not shorter than fourth, sometimes in- 

 termediate between fifth and sixth. Tail about three-fourths as 

 long as wing (much shorter than distance from bend of wing to end of 

 secondaries), even or very faintly emarginate or double-rounded, 

 the rectrices moderately broad, with broadly rounded tip. Tarsus 

 about one-fourth to nearly one-third as long as wing, rather slender; 

 acrotarsium extending entirely across outer side of tarsus, but the two 

 edges widely separated by a broad nonscutellate strip occupying the 

 posterior half of inner side of the tarsus; middle toe, without claw, de- 

 cidedly more than half as long as tarsus, its basal phalanx wholly 

 united to outer toe and at least half connected with inner toe ; outer 

 toe, without claw, reaching about to middle of subterminal phalanx! 

 of middle toe, the inner slightly but decidedly shorter; hallux about 

 as long as inner toe, its claw decidedly shorter than the digit; all the 

 claws rather strongly curved, sharp, compressed. 



Coloration. — Above plain gray or olive, the wings dusky with pale 

 edgings, some species with the middle and greater coverts more or less 

 broadly tipped with pale yellowish olive, dull whitish, or cinnamome- 

 ous ; under parts grayish white, tinged with pale gray on chest and 

 sides, or pale yellow, with or without olive shading on chest and sides, 

 the throat sometimes pale grayish. 



Range. — Southwestern border of United States to Ecuador, Guiana, 

 and southeastern Brazil. (About ten species and subspecies.) 



KEY TO THE SPECIES AND SUBSPECIES OF CAMPTOSTOMA. 



a. Under parts pale grayish or pale olive-grayish anteriorly, whitish or yellowish white 

 posteriorly; wing-bands l)roader, cinnamomeous or liglit brownish in adults. 

 b. PiU'um darker olive than back, more distinctly crested; wing-bands much less 

 sharply defined; under wing-coverts })rimrose or pale straw yellow. (South- 

 western border < >f United States to southern Mexico. ) 



Camptostoma imberbe (p. 414). 



