C. ultramarina. Lower parts whitish, conspicuously different from the upper.
Tail nearly, or perfectly even.
Length, 13.00; tail even; bill, 1.50; tail, 7.00. Hab. Mexico … var. ultramarina.[59]
Length, 11.50; tail very slightly rounded (graduation, .25 only); bill, 1.28 and .35; tail, 50. Above bright blue, dorsal region obscured slightly with ashy; beneath dull pale ash, becoming gradually whitish posteriorly, the crissum being pure ash. Lores blue. Tarsus, 1.45; middle toe, .95. Wing-formula, 5, 4 = 6, 7, 3, 8, 9, 10, 2; first, 2.10 shorter than longest. Graduation of tail, .25. Hab. Lower Rio Grande … var. couchi.
Tail considerably rounded.
Colors as in couchi, but dorsal region scarcely obscured by ashy. Lores black. Wing, 7.50; tail, 7.50; bill, 1.30 and .40; tarsus, 1.60; middle toe, .90. Wing-formula, 5, 4, 6, 3 = 7, 8, 9, 2; first, 2.75, shorter than longest. Graduation of tail, 1.15. Hab. Mexico (Orizaba, Mirador, etc.) … var. sordida.[60]
Graduation of the colors as in sordida, but the blue, instead of being a bright ultramarine, is very much paler and duller, and with a greenish cast, the whole dorsal region decidedly ashy; ash of the pectoral region much paler, and throat similar, instead of decidedly whitish, in contrast; pure white of posterior lower parts covering whole abdomen instead of being confined to crissum. Wing, 6.20; tail, 5.70; bill, 1.30 and .40; tarsus, 1.50; middle toe, .97. Wing-formula, fourth, fifth, and sixth equal; 7, 3, 8, 9, 2; first, 2.20, shorter than longest. Graduation of tail, .50. Hab. Southern Rocky Mountains (Fort Buchanan, and Copper Mines, Arizona) … var. arizonæ.
C. unicolor.[61] Lower parts bright blue, like the upper. Entirely
uniform rich ultramarine-blue; lores black. Wing, 6.70; tail, 6.70; bill, 1.30 and .50; tarsus, 1.45; middle toe, .95. Wing-formula, 5, 6, 4, 7, 3, 8, 9, 2; first, 2.60 shorter than longest. Graduation of tail, 1.50. Hab. Southern Mexico (Cordova, Mirador, etc.); Guatemala.
In the first section of this group we see the same indication of variation from a common type with the region that is so evident in Cyanura. Thus, Cyanocitta woodhousei differs from californica, much as Cyanura macrolopha does from C. stelleri (var. frontalis), in more slender bill and a greater percentage of blue; this invading the back and under parts, the lower tail-coverts especially. But here the parallel of modification ends, for the Mexican representative of the species (C. sumichrasti) appears to revert back to the characters of californica, having like it a minimum amount of blue, though this almost obliterates the superciliary stripe of white. In this respect there is more resemblance to the case of Pipilo fusca and its three races in the three regions inhabited by these representative forms of Cyanocitta californica; for, while the Mexican (P. fusca) and Californian (P. crissalis) are very much alike, the one from the intervening region (P. mesoleuca) is more different from the two extreme races than they are from each other.