Page:Birds of North and Middle America partV Ridgway.djvu/188

very slightly protruded; wing less than four times as long as tarsus; inner webs of remiges with an extensive basal area of ochraceous or pale tawny.

Premnornis (extralimital).^[1]

ee. Wing shorter (less than three and a half times as long as tarsus) and more rounded, the primaries exceeding secondaries by less than length of exposed culmen; bill relatively longer, the exposed culmen as long as middle toe without claw; inner webs of, remiges without buff or ochraceous cross-band or basal area.

Premnoplex (p. 180).

dd. Tarsus longer than middle toe with claw; outer toe with second phalanx entirely free from middle toe, the first phalanx also often partly free.

e. Basal phalanx of middle toe partly free from outer toe; bill more subulate or terete, with culmen more or less distinctly curved (at least terminally), the mesorhinium more or less rounded or else much compressed; wing relatively shorter and more rounded, the longer primaries exceeding secondaries by less than length of exposed culmen; no tuft on sides of neck; smaller forms (wing less than 80 mm.) (Synallaxeæ.)

f. Rectrices 12.

g. Tail much shorter than wing; hallux (without claw) longer than outer toe (without claw); wing four times as long as tarsus.

Siptornis (extralimital).^[2]

gg. Tail longer (sometimes very much longer) than wing; hallux (without claw) not longer than outer toe (without claw); wing not more than three and a half times as long as tarsus (usually much less).

h. Tarsus at least one-third as long as wing; frontal feathers extending farther forward, covering most of nasal operculum and concealing greater part of nostril.

i. Bill much stouter, with culmen much more strongly curved, more compressed, and sharply ridged; rictus abruptly and strongly deflected.

j. Tarsus decidedly more than one-third as long as wing; wing about two-thirds as long as tail; mesorhinium elevated, extremely compressed.

Drioctistes (extralimital).^[3]

jj. Tarsus not more than one-third as long as wing; wing more than three-fourths as long as tail; mesorhinium not elevated nor unusually compressed.

k. Wing only four-fifths as long as tail, the latter graduated for nearly two- thirds its length; tarsus not longer than middle toe with claw; bill relatively longer and narrower; feathers of chest with thickened or widened shafts.

Phaceloscenus (extralimital).^[4]

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1. Premnornis Ridgway, Proc. Biol. Soc. Wash., xxii, April 17, 1909, 71. Type, Margarornis guttata Lawrence. (Colombia and Ecuadór; monotypic.)
   This genus presents a very close superficial resemblance to the automoline genus Heliobletus Reichenbach (see p. 162) but may easily be distinguished by the very different nostrils and other structural characters.
2. Siptornis Reichenbach, Handb. der Spec. Orn., 1853, 171. Type, Synxillaxis striaticollis Lafresnaye. (Colombia and Ecuadór; monotypic.)
3. Drioctistes Ridgway, Proc. Biol. Soc. Wash., xxii, April 17, 1909, 71. Type, Thripophaga sclateri Berlepsch. (Southeastern Brazil; Bolivia?; three species?.)
   I have not seen Anabates erythrocephalus Maximilian nor Thripophaga fusciceps Sclater, one or both of which may be congeneric with Drioctistes sclateri. The genus is exceedingly distinct from Thripophaga.
4. Phaceloscenus Ridgway, Proc. Biol. Soc. Wash., xxii, April 17, 1909, 71. Type, Anumbius striaticollis D'Orbigny and Lafresnaye. (Argentina and Uruguay; monotypic?.)