60 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
Adult female—Pileum pale cinnamon to russet, more or less dis- 
tinctly streaked with dusky; back, scapulars, rump, and upper tail 
coverts plain olive; tail brownish olive or olive-brown; general color 
of wings olive (paler on edges of primaries), the lesser and middle 
wing-coverts darker (sometimes blackish), each with a terminal spot 
of buff, the greater coverts with a buffy spot on tip of outer web; 
auricular region olive or buffy grayish, very narrowly streaked with 
whitish or buffy; suborbital and malar regions pale buffy, barred or 
flecked with dusky; chin and throat dull buffy whitish, usually with 
more or less distinct narrow streaks of dusky; rest of under parts 
buff (more or less deep) medially, this passing into olive on sides and 
flanks, the chest sometimes streaked with dusky; under wing-coverts 
mostly pale buff or dull buffy whitish, the inner webs of remiges 
broadly edged with the same; maxilla dusky brown, mandible dull 
whitish (in dried skins); legs and feet horn color (in dried skins); 
length (skins), 97-112 (103); wing, 56-60.5 (58.2); tail, 29-35.5 
(32.2); culmen, 14.5-16.5 (15.4); tarsus, 18-21 (19.6); middle toe, 
11-12.5 (11.9).¢ 
Immature male.—Similar to the adult female but grayer above and 
more whitish beneath. 
Costa Rica (Angostura; Talamanca; San Carlos; La Balsa; Dos 
Novillos; Siquirres; Guaécimo; Guapiles; El Hogar; Carillo; La Chris- 
tina; Rio Reventazén; Rio Sicsola; Miravalles; La Vijagua). 
Dysithamnus striaticeps LawRENcE, Ann. Lyc. Nat. Hist. N. Y., viii, May, 1867, 
130 (Angostura, Costa Rica; coll. U. 8. Nat. Mus.); ix, 1868, 107 (do.).— 
Frantzivs, Journ. fiir Orn., 1869, 305 (Costa Rica)—Bovucarp, Proc. Zool. 
Soc. Lond., 1878, 60 (San Carlos, Costa Rica).—Zrtrep6én, Anal. Mus. Nac. 
Costa Rica, 1887, 115 (Angostura, Costa Rica).—SciaTER, Cat. Birds Brit. Mus., 
xv, 1890, 223 (‘‘Valza,”’ i. e., La Balsa, Costa Rica)—Satvin and Gopman, 
Biol. Centr.-Am., ii, 1892, 208.—UnpERWwoop, Ibis, 1896, 440 (Volcan de 
Miravalles, Costa Rica)—Carriker, Ann. Carnegie Mus., vi, 1910, 606 
(Caribbean foothills, 800-1,500 ft., Costa Rica; habits; descr. nest and eggs). 
[Dysithamnus] striaticeps SctatER and Satvin, Nom. Av. Neotr., 1873, 70.— 
SHarpe, Hand-list, iii, 1901, 19. 
Genus MYRMOTHERULA Sclater. 
Myrmotherula ScuatER, Proc. Zool. Soc. Lond., 1858, 234. (Type, Muscicapa 
pygmzxa Gmelin.) ; 
Myrmotherium (emendation) Casanis and Heinz, Mus. Hein., ii, July, 1859, 
12, footnote. 
Very small Formicariide (length less than 100 mm.) with bill 
slender, nearly as long as head, tail less than two-thirds (sometimes 
less than half) as long as wing, and plumage either conspicuously 
streaked or else mostly uniform gray or slate color. 
Bill slender, depressed, nearly as long as head, its width at frontal 
antiz very much greater than its depth at same point, and equal to 
about half the distance from nostril to tip of maxilla or less; culmen 
«Ten specimens. 
