Small Formicariidæ resembling Myrmotherula but differing in relatively much longer tail (much more than half to more than two-thirds as long as wing), much stouter and relatively shorter and less depressed bill, the adult males neither streaked nor plain gray or slaty.
Bill decidedly shorter than head, rather stout, not depressed basally, its width at frontal antiæ about equal to or very little greater than its depth at same point and equal to less to slightly more than half the distance from nostril to tip of maxilla; culmen distinctly and rather sharply ridged, straight or nearly so for most of its length, rather strongly and abruptly decurved terminally, the tip of maxilla minutely but distinctly uncinate; tomium nearly straight, that of maxilla distinctly, that of mandible slightly notched subterminally; gonys faintly convex (more decidedly so basally). Nostril exposed, posteriorly nearly (sometimes quite) in contact with feathering of latero-frontal antiæ, roundish or broadly oval, margined for basal half by the membraneous cover of nasal fossæ (this sometimes extending along upper margin as a narrow "operculum"); and with a conspicuous internal tubercle. Rictal bristles present but minute (practically obsolete); feathers of chin, malar antiæ, and lores with slender terminal setæ. Wing moderate, with longest primaries distinctly longer than secondaries; sixth and seventh, or fifth, sixth, and seventh, primaries longest, the tenth (outermost) slightly more than one-half to nearly two-thirds as long as the longest, the ninth about as long as secondaries or a little shorter. Tail much more than half to more than two-thirds as long as wing, much rounded, the rectrices (12) moderately broad to rather narrow, rounded terminally. Tarsus decidedly longer than exposed culmen, less than one-third as long as wing (except in M. ornata), the acrotarsium distinctly scutellate, the planta tarsi usually fused (at least in part) or with the scutella somewhat indefinite as to form and arrangement (with a general tendency toward two longitudinal series); middle toe, with claw, decidedly shorter than tarsus; outer toe, without claw, reaching to beyond middle of subterminal phalanx of middle toe, the inner toe slightly shorter; hallux about as long as inner toe but much stouter; basal phalanx of middle toe wholly united to outer toe, for about half its length to inner toe; claws moderate in size and curvature, that of the hallux decidedly shorter than the digit. Plumage soft, lax, and blended, that of rump and flanks much elongated and fluffy; feathers of pileum not elongated.
Coloration.[1] — Adult males plain gray or slate color above, the
wings black, spotted with white, the tail black with white tip to
- ↑ Not having been able to examine much the greater number of the species referred by Dr. Sclater to Myrmolherula (sec note on page 62) I am not able to define the full range of variation as to coloration in this group.
