BIRDS OF NORTH AND MIDDLE AMERICA. 127 
(at least posteriorly) by an extension of the membraneous integu- 
ment of the nasal fosse, an internal tubercle or facet visible within 
the posterior portion. Rictal bristles present, but inconspicuous; 
feathers of chin, malar antix, and loral region with distinct terminal 
sete. Wing moderate or rather large, with longest primaries extend- 
ing decidedly beyond secondaries; sixth and seventh, or seventh, 
primaries longest, the tenth (outermost) three-fifths as long as the 
longest, or slightly more, the ninth equal to or slightly longer than 
secondaries. Tail slightly more than one-half to three-fifths as long 
as wing, slightly rounded, the rectrices (12) rather broad, rounded 
terminally. Tarsus much longer than whole culmen, a little less than 
two-fifths as long as wing, the acrotarsium indistinctly scutellate 
(scutella sometimes obsolete except on lower portion), the planta 
fused, at least for greater part; middle toe, with claw, much shorter 
than tarsus; outer toe, without claw, reaching to about middle of 
subterminal phalanx of middle toe, the inner toe decidedly shorter; 
hallux equal to or slightly longer than inner toe; basal phalanx of 
middle toe wholly united, the second phalanx partly united, to outer 
toe (the adhesion involving the first two phalanges of outer toe), 
united for half its length or more to inner toe; claws rather large, 
moderately curved, extremely compressed, that of the hallux shorter 
than the digit (but sometimes nearly as long). Plumage full, soft, 
and blended, that of rump and flanks more elongated and lax; 
feathers of pileum not elongated. 
Coloration. Adult males gray and black above, the back with 
white spots or lunulate bars, the wing-coverts, tertials, and tail 
tipped with white; or back rufous or chestnut, with a concealed patch 
of white, the wing-coverts, tertials, and tail tipped with cinnamon- 
rufous; throat black, rest of under parts white, passing into gray or 
buffy on flanks, the chest spotted with black, or whole under parts 
plain gray. Adult females somewhat like males, but browner above 
with markings fulvous or buffy instead of white, the throat whitish, 
and black markings of chest replaced by brownish, or (in slate- 
colored species) head and under parts rufescent or the general color 
of under parts gray, with white throat and dusky flanks.? 
Range.—Costa Rica to western Ecuadér, Amazon Valley, and 
Guiana. (Six species. ?)® 
@ On account of insufficiency of material, I am not able to give the full range of color 
variation in this group. 
> Of the species referred to the genus Hypocnemis by Dr. Sclater and other recent 
authors I have seen in this connection only H. cantator (type of the genus), H. pecilo- 
nota (Cuvier), H. lepidonota Sclater and Salvin, H. leucophrys (Tschudi), H. myio- 
therina (Spix), H. lugubris (Cabanis and Heine), H. nevia (Gmelin), and H. nxvioides 
(Lafresnaye). The second, third, seventh, and eighth of these I have removed from 
Hypocnemis on account of the very different amount of adhesion of the anterior toes 
