750 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



bands across wing; an indistinct supra-auricular streak of paler olive; 

 chin whitish; throat, chest, and sides of breast pale brownish olive; 

 rest of under parts pale yellow (between sulphur and straw yellow), 

 the sides and flanks tinged with olive. 



Adult male.— Length (skins), 112-133 (121.2); wing, 54-60 (56.5); 

 tail, 53-57(54.7); exposed culmen, 9.5-11 (10.1); tarsus, 20-21.5(20.9).' 



Ad'idt female.— 'Length (skins), 111-133 (119.7); wing, 53-58.5 (55.1); 

 tail, 52-55.5 (53.5); exposed culmen, 10-11 (10.4); tarsus, 20-21.5 (20.9).' 



Nicaragua and Costa Rica (San Jose; Cartago; San Juan; Guaitil; 

 Grecia; Alajuela, etc.) 



Basileuterus delatlrii Bonaparte, Oompt. Rend., xxxviii, 1854, 383 (Nicaragua).— 

 Cabanis, Journ. fiir Orn., 1860, 325 (Costa Eica) .— Cherrie, Proc. U.S. 

 Nat. Mus., xiv, 1891, 340 (crit.; Costa Eica), 527 (San Jos6, Costa Eica; 

 descr. young); Auk, ix, 1892, 22 (San Jos^ Costa Rica; descr. nest and eggs) ; 

 Expl. Zool. Costa Eica, i, Aves, 1893, 14 (Boruca and Buenos Aires, s. w. 

 Costa Rica). 



Basileuterus deloiirei Lantz, Trans. Kansas Ac. Sci. for 1896-97 (1899), 223 

 (Grenada, Nicaragua). 



Blasileuterus] delatru Ridgway, Man. N. Am. Birds, 1887, 532, part. 



Basileutei-us mesochryms (not of Sclater, 1860) Baird, Review Am. Birds, 1865, 

 250, part (San Jose, Costa Rica). — Lawrence, Ann. Lye. N. Y., ix, 1868, 95 

 (San Jos^, Guaitil, and Grecia, Costa Rica). — Frantzius, Journ. fiir Orn., 

 1869, 294 (San Jos6, Costa Rica).— Boucard, Proc. Zool. Soc. Lond., 1878, 

 52 (San Josi5 and Cartago, Costa Rica). — Salvin and Godman, Biol. Centr.- 

 Am., Aves, i, 1881, 176, part (San Jos6, Guaitil, Grecia, and Irazii, Costa 

 Eica).— NuTTiNt;, Proc. U. S. Nat. Mus., v, 1883, 499 (San Jos6).— Zeledon, 

 Anal. Mus. Nac. Costa Eica, i, 1887, 107 (San Jos6, Alajuela, Naranjo de 

 Cartago, Grecia, and Monte Redondo, Costa Eica). — Underwood, Ibis, 1896, 

 434 (Volcan de Miravalles, Costa Eica). 



l^Basileuterus] rnesochrysus Sclater and Salvin, Nom. Av. Neotr., 1873, 10, part 

 (Costa Eica). 



[Basiteuteriis delattrii.l Subsp. a. Basileuterus rnesochrysus Sharpe, Cat. Birds 

 Brit. Mus., X, 1885, 396, part (Grecia and Irazu, Costa Eica). 



BASILEUTERUS RUFIFRONS MESOCHRYSUS (Sclater). 

 SCLATER'S WARBLER. 



Similar to B. r. delattrii, but back, etc. , lighter and clearer (more 

 yellowish) olive-green, gray of hindneck lighter and clearer and more 

 strongly contrasted with olive-green of the back, and yellow of under 

 parts averaging brighter, with sides and flanks more faintly tinged 

 with olive; tail relatively shorter. 



Aditlt male.— Length (skins), 108-116 (110.7); wing, 55-59 (56.5); 

 tail, 48-53 (50.1); exposed culmen, 10-11 (10.2); tarsus, 20-21 (20.2).' 



Adult female.— Length (skins), 102-118 (109); wing, 53-56(54.7); 

 tail, 47.5-54 (50.2); exposed culmen, 10-10.5 (10.3); tarsus, 20.5-21 

 (20.7).' 



' Four specimens. ^ Six specimens. ' Three specimens. 



