Is2 



Ridgway, Geographical Variation in Sialia mexicana. Anril 



slate. Chin, throat, and upper part of" chest dull smalt-blue (decidedly, 

 but not abruptly, paler and duller than top and sides of head) ; sides of 

 chest, sides, and flanks chestnut-cinnamon, inclining to mars brown, 

 this color extending rather narrowly across the upper breast, where, how- 

 ever, somewhat streaked with blue along the median line; lower median 

 portion of breast, upper part of belly, axillars, and under wing-coverts, 

 light, grayish smalt-blue, inclining to campanula-blue; the under tail- 

 coverts similar but still paler, with basal portion and edges of feathers 

 grayish white; lower belly and anal region dull grayish white. Bill and 

 feet black. Total length (skin), 6.20; wing, 4.62; tail, 2. 88' ; exposed 

 culmen, 0.50; tarsus, 0.85 ; middle toe, 0.62. 



Adult male in autumn (No. 135,709, Villar, San Luis Potosi, Mexico, 

 Sept. 28, 1892; E. W. Nelson): Above purplish cobalt-blue, the back 

 and scapulars overlaid or obscured by grayish brown wash occupying, 

 broadly, the tips of the feathers; top of head similarly but more faintly 

 obscured by brownish gray. Otherwise similar to the breeding plumage, 

 as described above, but blue of under parts much paler (intermediate 

 between 'campanula' blue and 'flax-flower' blue), except on axillars, under 

 wing-coverts, and under tail-coverts, which are campanula blue, the 

 latter with whitish margins. Cinnamon-chestnut of breast extending 

 continuously across. Total length (skin), 6.65; wing, 4.35; tail, 2.78; 

 tarsus, 0.82; middle toe, 0.60. 



Adult female in breeding season (No. 135,705, Mt. Orizaba, Puebla, 

 April 19, 1893; E. W. Nelson): Above dull grayish blue, becoming 

 bright blue (intermediate between 'campanula' and 'cobalt') on rump, upper 

 tail-coverts and tail, dullest on the back, where inclining to drab-brown 

 on scapular region, especially anterior portion ; outermost primary with 

 outer web broadly margined with pure white, and outer web of exterior 

 tail-feather almost wholly pure white. Chin, throat, and malar region 

 dull light bluish gray, the chin and upper throat very indistinctly mottled 

 with darker; entire chest (except upper median portion, where mixed 

 with gray of throat), upper breast, sides, and flanks, uniform rufous- 

 cinnamon, deepest on sides of chest; median portion of lower breast light 

 dull gray, fading to dull whitish gray on belly and anal region; under 

 tail-coverts light grayish blue, broadly margined with white. Bill and 

 feet black. Total length (skin), 6.20; wing, 4.30; tail, 2.70; exposed 

 culmen, 0.43; tarsus, 0.82; middle toe, 0.60. 



Adult fetnale in tvinler (No. 135,711, Mt. Popocatapetl, Mexico, 

 February 24, 1S93; E. W. Nelson): Very similar to the specimen (in 

 breeding plumage) described above, but back and scapulars uniformly 

 warm brown ('Prout's' brown), and cinnamon-color of breast, etc., deeper 

 as well as much more extensive (covering entire chest and breast, as well 



1 Extreme and average measurements of wing and tail of 7 adult males are as 

 follows: Wing: Average, 4.38; longest, 4.62 ; shortest, 4.18. Tail: Average, 2.69; 

 longest, 2.88 ; shortest, 2.50. 



