Page:Birds of North and Middle America partV Ridgway.djvu/41

Rh ::::: f. Tail much shorter than wing (not more than three-fourths as long, usually much less).
 * g. Tail little if any more than half (sometimes much less than half) as long as wing.
 * h. Bill small and very slender, the exposed culmen shorter than middle toe without claw

Rhopias (extralimital).
 * hh. Bill larger and stouter, the exposed culmen longer than middle toe without claw.
 * i. Planta tarsi scutellate on each side; maxilla slightly decurved terminally; gonydeal angle very slight; plumage streaked; no white band across rump

Myrmotherula (p. 60.)
 * ii. Planta tarsi scutellate on posterior portion of outer side only; maxilla straight throughout (only the extreme tip decurved); gonydeal angle prominent; plumage spotted; a white band across rump

Dichrozona (extralimital).
 * gg. Tail much more than half to more than two-thirds as long as wing.

Myrmopagis (p. 65).
 * f. Tail nearly as long as wing, sometimes longer.
 * g. Nostril slit-like, much narrower than the broad operculum; tarsus nearly half as long as wing. (Rectrices 10.)
 * h. Rictal bristles obsolete; feathers of chin and forehead without trace of terminal setæ; tarsus much less than twice as long as middle toe without claw, the plantar scutella very distinct on both sides.

Rhoporchilus (extralimital).
 * hh. Rictal bristles obvious (though small); feathers of chin and forehead with distinct terminal setæ; tarsus twice as long as middle toe without claw, the plantar scutella indistinct (especially on inner side)

Myrmorchilus (extralimital).
 * gg. Nostril broadly oval, much broader than the narrow (sometimes obsolete) operculum; tarsus less than half as long as wing.
 * h. Rectrices 12.
 * i. Pileum not black, or else back and rump also black; back, scapulars, and rump brownish slate, brown, rufescent, or black, concolor with pileum; adult male with at least chin, throat, chest, and part of breast black

Microrhopias (p. 75).
 * ii. Pileum (in adult male) black, conspicuously contrasted with bluish gray of back, scapulars, and rump; chin and throat