Genus MICRORHOPIAS Sclater.
- Microrhopias Sclater, Cat. Am. Birds., 1862, 182. (Type, Thamnophilus quixensis Cornalia.)
Small to very small Formicariidæ (length about 105-135 mm.) with long, graduated tail of 12 round-tipped rectrices (nearly as long as to longer than wing), tarsus much less than half as long as wing, nostril broadly oval (much broader than the narrow, sometimes nearly obsolete, operculum), the adult males with at least the chin, throat, chest, and median portion of breast black, and wing-coverts tipped with white.
Bill shorter than head, moderately stout, not compressed, its width at frontal antiæ little if any greater than its depth at same point and equal to about half the distance from nostril to tip of maxilla; culmen distinctly but not sharply ridged, nearly straight for basal half (more or less) more and more decurved terminally, the tip of maxilla slightly though distinctly uncinate; tomia straight or nearly so, distinctly notched subterminally, the notch near tip of mandibular tomium less distinct; gonys gently convex, less so terminally. Nostril exposed, longitudinally oval, nearly in contact with feathering of latero-frontal antiæ, the superior operculum very narrow or practically obsolete. Rictal bristles well developed in M. boucardi and M. consobrina,[1] very minute (practically obsolete) in M. intermedia, M. grisea, M. rufatra, and allies; feathers of chin and loral region with slender terminal setæ. Wing moderate, with longest primaries extending, more or less decidedly, beyond secondaries; fifth and sixth, sixth and seventh, or fifth, sixth and seventh, primaries longest, the tenth (outermost) one-half to three-fifths as long as the longest, the ninth shorter than secondaries. Tail nearly as long as to longer than wing, graduated (graduation equal to length of tarsus or more), the rectrices (12) rather broad, rounded terminally. Tarsus longer than whole culmen, one-third (M. boucardi, M. consobrinus) to two-fifths as long as wing (M. grisea, M. intermedia, M. rufatra), distinctly scutellate, the plantar scutella in two longitudinal series but sometimes partly fused or obsolete; middle toe, with claw, much shorter than tarsus; outer toe, without claw, reaching to slightly 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 its digit. Plumage full, lax, and blended, that of the rump and flanks elongated and more fluffy; feathers of pileum not elongated.
- ↑ Probably also in the closely related M. quixensis and M. bicolor, which, however, I have not seen.
