Geographical Distribution in Birds. 455 
black, there being more of the latter color in the Mexican than 
in the Arizonan specimens. By the time we reach the latitude 
of Mirador and Micatlan, the black entirely replaces the olive- 
green; the bird now is the var. Mexicana,* and continues with 
nearly the same characteristics south to Costa Rica and Pan- 
ama, from which latter countries we find specimens in which 
the black is often appreciably more intense and lustrous than 
* 
in those from Mexico. These three forms all have white on 
size. These equatoreal specimens (var. Columbiana)+ exhibit 
ward, first through var. nigricapillus§ (Costa Rica and Panama), 
and finally ending in var. nigriceps| (Ecuador), which has the 
* CHRYSOMITRIS PSALTRIA var. MEXICANA. 
Carduelis Mexicana Swains., Syn. Birds Mex., Phil. Mag., 1827, 435.—Chry- 
somitris M. Bonap., Consp., 1850, 516.—Baird, B. N. Am., 1858, 423, pl. 
iy, t 2: 
Hab. Middle America (coast to coast), from Northern Mexico to Costa Rica. 
+ Curysomrris PsALTRIA var. COLUMBIANA. 
Chrysomitris Columbiana Lafr., Rev. Zool. 1843, 292.—Baird, B. N. Am., 
1858, 423.—Sclater, Catal., 1862, 124. 
Hab. Bogota to Panama. 
¢ Mytarcuus Lawrenctt var. LAWRENOT. : 
Tyrannula Lawrencii Giraud, 16 sp. Texas Birds, 1841, pl. ii—Myiarchus L. 
ird, B. N. A., 1858, 18.—Sclater, Cat. Am. B., 1862, 233.—Coues, P. A. N. 
8., July, 1872. 
Hab. Mexi 
Myiarchus nigricapilus “ Cabanis, MS.,” Sclater, Cat. Am. B., 1862, 233.—M. 
| Mytarcuvs LAWRENCI! var. NIGRICEPS. 
Myiarchus nigriceps Sclater, P. Z. S., 1860, pp. 68, 295 (Ecuador).—Ib., Catal. 
Am. B., 1862, 234.—Coues, P. A. N.S, July, 1872. 
Hab. Panama to Ecuador. 
