BIRDS OV NORTH AND MIDDLE AMERICA. 193 



overhung by a convex horny operculum (nearly hiding- the nostril in 

 A. holo.^e7'iceiis)\ posterior end of nostril touching feathering of loral 

 antiffi. Wing short (a little more than three to about four times as 

 long as culmen), short-tipped (primaries exceeding secondaries by less 

 than distance from nostril to tip of maxilla ^), excessiv^ely rounded; 

 ninth primary .shorter than tirst, the fourth to sixth longest; inner 

 webs of outer three or four faintly sinuated. Tail nearly as long as 

 wing, much rounded, the rectrices broad and rounded at ends. Tarsus 

 longer than culmen, stout, the anterior scutella very distinct; middle 

 toe, with claw, shorter than tarsus but equal to or slightly longer than 

 culmen; outer toe with claw reaching to or beyond^ base of middle 

 claw, the inner slightly shorter; hallux slightly shorter than inner toe 

 but much stouter, its claw slightly shorter than the digit, strongly 

 arched. 



Coloration. — Uniform black (more slaty black in females), the bill 

 light colored. 



Range. — Southern Mexico to Peru, Argentina, Paraguay, and south- 

 ern Brazil. (Three species.) 



While much alike in general appearance, the two commonly known 

 species of this genus arc really very distinct in certain structural details 

 and may not be truly congeneric, ji.- solitarius has the nostrils much 

 more open, those of A. holosericeits being nearly closed by the much 

 more developed convex overhanging horny operculum; A. solitarkis 

 has a well-developed crest of soft, decumbent, elongated feathers, 

 while in A. holosericeus there is no crest; A. soUtarius has the wing- 

 tip much longer, the primaries exceeding the secondaries b}^ about the 

 distance from the nostril to the tip of the maxilla, while in A. holoseri- 

 ceus they project for not more than the basal depth of the bill; in A. 

 soUtarius the outermost (ninth) primary is about equal to the seconda- 

 ries, the eighth being longer than the third, while in A. holosericeus 

 the ninth is very much shorter than the shortest secondaries, the 

 eighth being shorter than the first and about equal to the shorter sec- 

 ondaries. The remiges and rectrices are also more firmly webbed in 

 A. soUtarius. 



A. holosericeus "is a bird of singular habits, suggesting both an 

 Oriole and a Woodpecker. It hunts along limbs as patientl}^ as a 

 Creeper, tapping here and there or pouf.ding vigorously in its efforts 

 to secure food from cracks and crevices. In short flights it presents 

 a laughable appearance. It progresses by jerky wing-beats, and at 

 the end of each stroke the tail is thrown forward over the head." * 



^ Very slightly exceeding secondaries in A. holosericeus. 



'^In A. soUtarius. 



=» Chapman, Bull. Am. Mus. Nat. Hist., viii, 1896, 280. 



3654— VOL 2—01 13 



