smoke gray; back, scapulars, wing coverts, rump, and upper tail coverts plain Bluish Black; rectrices (except middle pair) with large patch of White midway between base and tip, rest plain Bluish Black; chest, breast, and anterior parts of sides plain Bluish Gray-Green, much lighter than back, and fading into paler Gray on throat; abdomen and thighs White; flanks and posterior part of sides Olive-Yellow or Yellowish Olive; under tail coverts Lemon Yellow; bill, legs and feet Black. Coloration of adult females: Head plain Smoke Gray, passing into White on frontals, malars, and chin; back, scapulars, wing coverts, and rump Hair Brown; upper tail coverts Dark Gull Gray; remiges and rectrices Black with faint Dusky Green gloss, edged with Gull Gray; chest Dark Grayish Brown lightening to Wood Brown on sides and flanks; abdomen White; under tail coverts Yellow Ocher. Coloration of young: As in adult female, but paler throughout.

Measurements.—In adult male, wing 94.0, and tail 104.2; in adult female, wing 93.3, and tail 94.8; both sexes, culmen 11.1, and tarsus 18.7.

Range.—Mountainous districts of central and southern Mexico, in states of Durango, Zacatecas, Hidalgo, México, Oaxaca, Colima, Morelos, Veracruz, San Luís Potosi, Guerrero and Michoacán.

Diagnosis.—Coloration of adult male: Upper parts darker bluish than in P. c. cinereus; venter paler; flanks Olive-Green rather than Olive as in P. c. cinereus. Coloration of adult female: Like female of P. c. cinereus but colors darker throughout; dorsum more olivaceous.

Measurements.—In adult male, wing 89.4, and tail 97.1; in adult female, wing 89.4, and tail 93.3; both sexes, culmen 11.7, and tarsus 17.3.

Range.—Western Guatemala, in subtropical and temperate zones.

Diagnosis.—Coloration of adult male: Forehead and crown Pale Grayish Blue, slightly paler anteriorly; orbital ring Lemon Yellow; rest of head and neck, including crest, Olive-Yellow; throat paler and tinged with Light Gull Gray; back, scapulars, rump, upper tail coverts and wing coverts uniform Bluish Slate-Black; chest and breast similar but paler; sides and flanks Yellowish Olive-Green; thighs, lower abdomen, and under tail coverts Lemon Yellow; remiges, primary coverts, and tail Black, glossed with Bluish Black and edged with Gull Gray; inner webs of rectrices (except two middle pair) with large middle patch of White; bill, legs, and feet Black. Coloration of adult female: Forehead and crown Pale Gull Gray, becoming paler anteriorly; rest of head, together with neck, back, scapulars, rump, and wing coverts plain Yellowish Olive Green; chest and breast similar but more grayish; lower abdomen and flanks White tinged with Yellowish Olive; under tail coverts Olive-Gray; remiges, primary coverts, and rectrices Black with Gull Gray edges. Coloration of young: Dorsum plain Light Grayish Olive; upper tail coverts Brownish Olive; underparts Grayish Olive anteriorly, becoming more Yellowish Olive on abdomen; under tail coverts pale Yellowish Olive with Grayish Olive base; bill and feet Brownish Drab.

Measurements—In adult male, wing 96.2, and tail 135.7; in adult female, wing 93.9, and tail 113.7; both sexes, culmen 12.6, and tarsus 19.1.

Range.—Highlands of Costa Rica and extreme western Panamá.

Diagnosis.—Tail almost as long as wing; head with pointed crest of narrow, separated feathers; rectrices without white; bill narrow, compressed terminally; conspicuous white patch under wing; nostril small, exposed; rictal bristles distinct; tail slightly rounded.

Diagnosis.—Coloration of adult male: Uniform glossy Bluish Black; inner webs of primaries except innermost pair with middle portion White; bill, legs, and feet Black. Coloration of adult female: Plain Olivaceous Black, longer feathers of crest Black, edged with Gull Gray; remiges and rectrices Dusky Drab to Black; rectrices and coverts margined by White; bill and feet Brownish Drab to Dusky Brown. Coloration of young: Like adult female but more Brownish Drab.

Measurements.—No specimens examined; larger than P. n. lepida (Van Tyne, 1925).

Range.—Central and southern Mexico, in states of Coahuila, San Luís Potosi, Durango, Guanajuato, México, Puebla, and Veracruz.

Diagnosis.—Coloration same as P. n. nitens; separated by smaller size.

Measurements.—Wing 91.0, tail 90.3, culmen 11.5, tarsus 17.6.

Range.—Southwestern United States, from central California, southern Utah, and central western Texas southward to Cape San Lucas in Baja California, and into northwestern Mexico (Sonora and Chihuahua).

Diagnosis.—Wings long and pointed, reaching almost to tip of tail; first primary spurious; second primary longest; tail short and even; rictal vibrissae few and short; secondaries generally, and sometimes also rectrices, tipped with red, corneous appendages; nasal fossa partly filled with short, antrorse, close-set velvety feathers; plumage soft, silky; tail tipped with yellow band (red in B. japonica); sexes alike; humerus short with large external condyle; caudal muscles and pygostyle not well developed; bill flared widely at base; one genus, three species.

Range of subfamily.—Holarctic breeding area; wanders nomadically south in winter to Central America and West Indies, southern Europe and Asia.

Diagnosis.—As described for the subfamily.

Diagnosis.—Coloration of adults: Shading from Saccardo's Umber on dorsum to Bister on