212 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



gonys faintly convex basally, straight or faintly concave terminally, 

 the tip of maxilla sometimes slightly deciirved. Nostril exposed, 

 posteriorly in contact with loral feathering, rather small, roundish 

 or broadly oval, non-operculate, but margined above by very narrow 

 membranous rim. Rictal bristles wanting, and feathers of chin, 

 etc., without terminal setae. Wing moderate, much rounded, the 

 longest primaries exceeding secondaries by much less than length of 

 bill from nostril (except in A. leucophthalmus, in which the difference 

 between tip of secondaries and longest primaries nearly equals length 

 of exposed culmen) ; sixth, seventh, and eighth, sixth and seventh, 

 fifth, sixth, and seventh, or fifth and sixth primaries longest, the 

 tenth (outermost) less than two-thirds to three-fourths (A. leucoph- 

 thalmus) as long as the longest, the ninth longer than fourth (A. 

 leucophthalmus) to shorter than second (A. rubiginosus). Tail six- 

 sevenths as long as wing {A. leucophthalmus) to as long as wing, 

 graduated (graduation equal to from less than one-fourth, in A. 

 leucophthalmus to more than one-third, in A. verse-pacis, its total 

 length), the rectrices (12) rather broad, with tip rounded or slightly 

 subacuminate. Tarsus shorter than culmen (from base), a little 

 more than one -fourth (in A. leucophthalmus) to nearly one third (in 

 A. verse pads) as long as wing, distinctly scutellate; middle toe, with 

 claw, shorter than tarsus; outer toe, without claw, reaching to or 

 slightly beyond middle of subterminal phalanx of middle toe, the 

 inner toe slightly shorter; hallux nearly as long as outer toe, but 

 much stouter; basal phalanx of middle toe united for about half its 

 length to outer toe, for less than half to inner toe; claws moderate to 

 rather large, strongly curved, that of the hallux decidedly shorter 

 than the digit. 



Coloration. — Above plain brown (sometimes darker on pileum and 

 hindneck), the upper tail-coverts and tail (somethnes rump also) 

 cinnamon-rufous or chestnut; beneath plain tawny, cinnamon-brown, 

 or pale buffy (more brownish laterally) , the throat light russet, tawny, 

 ochraceous, buff, or whitish; foreneck sometimes faintly squamated 

 with brown or dusky; sometimes a tawny or ochraceous supra- 

 auricular stripe. Sexes alike. 



Range. — Southern Mexico to British Guiana, Peru, and south- 

 eastern Brazil. (About eighteen species.) '^ 



oOf these I have examined, in this connection, only the following: A. rubiginosus 

 (Sclater), A. versepacis Salvin and Godman, A. guerrerensis Salvin and Godman, A. 

 umbrinus Salvin and Godman, A. cervinigularis (Sclater), A. ochrolxmus (Tschudi), 

 A. pallidigularis Lawrence, A. leucophthalmus (Maximilian), and A. rufipevtus Bangs. 

 All these agree very well in structural characters except A. leucophthalmus, which is 

 conspicuously different in its relatively longer and much more pointed wing, much 

 less graduated tail, and much shorter gonys. 



