BIRDS OF NORTH AND MIDDLE AMERICA. 181 



flanks; rest of under parts, together with anterior portion of malar 

 region, white; axiUars, under wing-eoverts, and edges of inner webs 

 of remiges white; maxilla clear brownish, mandible much paler, or 

 dull brownish white (in dried skins); legs and feet dark brownish (in 

 dried skins). 



Adult 7/i«/tf.— Length (skins), 112-117 (134.4); wing, 60-63 (61); 

 tail, 48-53 (50.2); exposed culmen. 12; tarsus, 22-24 (23); middle toe, 

 10-12 (11)." 



Adult female.— l^engi\\ (skins), 113-122(118.6); wing, 60-61 (60.4); 

 tail, 50-53 (51); exposed culmen, 11-12 (11.2); tarsus, 22-23 (22.6); 

 middle toe, 10-11 (10.8)." 



Island of Cozumel, Yucatan. 



Vh-i'o balrdl Ridgway, Descr. New Species Birds from Cozumel, Feb. 26, 1885, 

 2; Proc. Biol. Soc. Washington, iii, IVIar., 1885, 22 (Cozumel Island, 

 Yucatan; coll. U. 8. Nat. Mus.) ; Proc. U. S. Nat. Mus., viii, 1885, 565 (full 

 description). 



T'[/reo] hairdi Riiig\v.\y, ^lan. N. Am. Birds, 1887, 477. 



VIREO ATRICAPILLUS Woodhouse. 

 BLACK-CAPPED VIREO. 



Adnlts {sexes aliJce^). — Lores and broad orbital ring white, the latter 

 interrupted for a short distance (1-3 mm.) on upper eyelid; rest of 

 head and neck, except chin and throat, uniform black (oldest birds?) 

 or black and slate-gray in variable relative proportion (younger birds?), 

 sometimes entirely slate-gray (birds in second year?); back, scapulars, 

 rump, upper tail-coverts, and lesser wing-coverts clear olive-green; 

 wings (except lesser coverts) and tail dull black or dusky with light 

 olive-green edgings (these broader and pale yellow on tertials, more 

 whitish on longer primarie.s), the middle and greater wing-coverts 

 broadly tipped with pale yellow (sulphur or primrose), forming two 

 conspicuous bands across wing; under parts, inchiding- chin and 

 throat, white, passing into light olive-vellow or pale yellowish olive- 

 green on sides and flanks; axi liars and under wing-coverts sulphur or 

 primrose yellow: inner webs of remiges edged with yellowish white; 

 maxilla black, mandible graj-ish blue; iris brownish red; legs and feet 

 grayish blue. 



"Five specimens. 



^Writers differ as to whether the sexes agree in color or not. The serie.^ exam- 

 ined, which, however, includes only one adult female (there are eighteen adult males), 

 if the sex has l)een correctly determined in all cases, shows that the sexes are alike 

 and that the presence of black on the head or its extent is ])robably a matter of age. 

 The grayer headed specimens invariably have the white of the under jiarts less pure, 

 iu this respect being more or less like young birds in their fii-st autunm, which lends 

 probability to the theory that relative age is the true explanation of the variations 

 noted. (See Brewster, Bull. Nutt. Orn. Club, iv, 100; Ragsdale, Bull. Nutt. Orn. 

 Club, V, 239; Goss, Auk, ii, 275, 276.) 



