54. BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
KEY TO THE SPECIES AND SUBSPECIES OF DYSITHAMNUS. = 
a. Pileum and hindneck at least partly slate color or slate-gray. (Adult males.) 
b. Pileum and hindneck without black or white markings. 
c. A narrow white spot or streak on lower edge of auricular region. (Southwestern 
Brazil; Bolivia?)........-..- Dysithamnus affinis, adult male (extralimital).¢ 
cc. No trace of white spot or streak on lower edge of auricular region. (Dyst- 
thamnus mentalts.) 
d. Under parts of body more deeply yellowish, strongly and abruptly con- 
trasted with grayish white of throat. (Southeastern Brazil; Paraguay.) 
Dysithamnus mentalis mentalis, adult male (extralimital).6 
dd. Under parts of body paler yellowish (sometimes white). 
e. Abdomen more or less yellowish; back more or less olivaceous, different 
from color of pileum and hindneck. 
j. Larger (wing 63.5-66.5). 
g. Paler. (Tobago.) 
Dysithamnus mentalis oberi, adult male (extralimital).¢ 
gg. Darker. (Colombia and Venezuela.) 
Dysithamnus mentalis semicinereus, adult male (extralimital).@ 
ff. Smaller (wing 57-62). (Panam4 to Guatemala.) 
Dysithamnus mentalis septentrionalis, adult male (p. 55). 
ee. Abdomen white; back slate color, concolor with pileum and hindneck. 
jf. Lighter and clearer slate color above, more extensively white beneath, 
the flanks paler and less olive or buffy brownish. (Trinid4d.) 
Dysithamnus mentalis andrei, adult male (extralimital).¢ 
@ Dysithamnus affinis Pelzeln, Orn. Bras., ii, Abth., 1869, 80, 149 (Villa Maria, . 
Brazil; coll. Vienna Mus.).—DJ[ysithamnus] a[ finis] afinis Hellmayr, Novit. Zool., 
xiii, Feb., 1906, 32, in text (crit.); Dysithamnus affinis affinis Hellmayr, Novit. Zool., 
xv, 1908, 69 (Faz. Esperanza, Brazil; crit.)—Dysithamnus olivaceus (not Thamno- 
philus olivaceus Tschudi) Sclater, Cat. Birds Brit. Mus., xv, 1890, 222, excl. syn. 
part.—Dysithamnus mentalis (not Myothera mentalis Temminck) Allen, Bull. Am. 
Mus. N. H., v, 1893, 118, excl. syn. (Chapada, Matto-Grosso, Brazil; crit.). 
b Myothera mentalis Temminck, Pl. Col., ii, livr. 30, Jan., 1823, text to pl. 179, 
fig. 8 (Brazil; coll. Vienna Mus.).—Daysthamnus mentalis Burmeister, Syst. Ueb. 
Th. Bras., ili, 1856, 82.—Dysithamnus mentais Sclater, Proc. Zool. Soc. Lond., 1858, 
221, part; Cat. Birds Brit. Mus., xv, 1890, 221; Allen, Bull. Am. Mus. N. H., ii, 
1889, 250.—D[ysithamnus] mentalis mentalis Hellmayr, Novit. Zool., xiii, Feb., 1906, 
32, in text (crit.).—M[ytothera] poliocephala Maximilian, Beitr. Naturg. Bras., iii, 
pt. ii, 1831, 1098 (s. e. Brazil; type now in coll. Am. Mus. Nat. Hist.) 
¢ Dysithamnus mentalis oberi Ridgway, Proc. Biol. Soc. Wash., xxi, Oct. 20, 1908, 
193 (Tobago; coll. U. 8. Nat. Mus.). 
@ Dysithamnus ‘semicinereus Sclater, Proc. Zool. Soc. Lond., 1855, 90, 147, pl. 97 
(Bogot4, Colombia; coll. P. L. Sclater); Cat. Birds Brit. Mus., xv, 1890, 221, part.— 
D{ysithamnus] mentalis semicinereus Ridgway, Proc. Biol. Soc. Wash., xxi, Oct. 20, 
1908, 193, in text. 
¢ Dysithamnus affinis andret Hellmayr, Novit. Zool., xiii, Feb., 1906, 31 (Caparo, 
Trinid4d; coll. Tring Mus.).—Dysithamnus mentalis spodionotus (not D. spodionotus 
Salvin and Godman) Chapman, Bull. Am. Mus., N. H., vi, 1894, 50 (Trinidéd). 
