BIRDS OF NORTH AND MIDDLE AMERICA. 35 
near base, more strongly decurved terminally, the tip of mandible 
distinctly but not strongly uncinate; maxillary tomium faintly con- 
cave, distinctly notched subterminally; mandibular tomium nearly 
straight, minutely but distinctly notched and toothed subterminally, 
the tip of mandible acute, recurved; gonys moderately convex, 
ascending terminally, rather prominent basally. Nostril exposed, 
broadly longitudinally oval, with the internal tubercle barely visible 
in upper posterior portion. Rictal bristles present but very small, 
shorter than the terminal setz to feathers of chin. Wing moderate, 
with longest primaries projecting slightly but decidedly beyond 
secondaries; fifth and sixth primaries longest, the seventh but little 
shorter; tenth (outermost) about three-fifths as long as longest, the 
ninth shorter than secondaries. Tail about as long as wing (at least 
five-sixths as long), much rounded (graduation equal to or exceeding 
length of exposed culmen), the retrices (12) moderately broad. 
rounded terminally. Tarsus equal to or longer than commissure, 
about one-third as long as wing, distinctly scutellate, the plantar 
scutella in two longitudinal series, elongate-quadrate or lozenge 
shaped; middle toe, with claw, much shorter than tarsus (toe alone 
shorter than exposed culmen); outer toe, without claw, reaching to 
or a little beyond middle of subterminal phalanx of middle toe, the 
inner toe a little shorter; hallux about as long as inner toe, but much 
stouter; basal phalanx of middle toe wholly united to outer toe, 
united to inner toe for about half its length; claws moderate in size 
and curvature, that of the hallux much shorter than its digit. Plum- 
ageé full, lax, and blended, that of the rump elongated, fluffy; feathers 
of crown and occiput (especially the latter) elongated, distinctly 
outlined, forming a distinct but not conspicuous decumbent crest. 
Coloration.— Adult males with under parts (usually the upper 
also) conspicuously barred with black and white, or else (in T. 
virgatus) dull slate-gray, streaked with whitish; adult females and 
young tawny or rufescent above, ochraceous or buffy below. 
NMidification.—Nest pensile, suspended from a fork like that of a 
Vireo. Eggs white or creamy white, marked with brownish spots or 
streaks. 
Range.—Southern Mexico to Cayenne, Paraguay, Bolivia, and 
Peru. (About ten species, not including subspecies.) 
KEY TO THE SPECIES AND SUBSPECIES OF THAMNOPHILUS.2 
a. Plumage wholly black and white, in transverse bars. 
6. Pileum wholly black. (Eastern Panam4, including San Miguél Island, and 
Caribbean coast of Colombia.) 
Thamnophilus radiatus nigricristatus, adult male (p. 37). 
@ Owing principally to lack of sufficient material this key is confined mainly to the 
forms belonging properly to the present work and is by no means as satisfactory as is 
desirable. 
