I DO Ridgway, Geographical Variation in Sialiamexicana. \ \ n ^\ 



Adult female in spring (same locality, May i, 1S89 ; A. W. Anthony) : 

 Top of head, hind-neck and sides of neck brownish gray distinctly glossed 

 with lavender-blue; ear-coverts deeper brownish gray, or drab, without 

 blue gloss; chin pale gray; throat and upper chest similar but tinged 

 with fawn-color; breast and sides russet-cinnamon, paler on flanks; 

 belly light smoke-gray; under tail-coverts light grayish blue, margined 

 with white, and with narrow dusky shaft-streaks. Back and scapulars 

 dull grayish brown, tinged with purplish cinnamon, the median portion 

 of the back glossed with grayish blue; lesser and middle wing-coverts 

 bright smalt'blue; greater coverts and tertials duller, more grayish, blue, 

 margined with dull light grayish; secondaries and primary-coverts dull 

 smalt-blue, dusky at tips, and edged with paler: primaries and rectrices 

 campanula-blue, becoming dusky at tips, the outer web of exterior 

 primary and tail-feathers broadly edged with white; lower back, rump, 

 and upper tail-coverts bright campanula-blue, or light smalt-blue. Bill 

 and feet black. Total length (skin), 6.40; wing, 4.15; tail, 2.80 1 ; 

 exposed culmen, 0.45 ; tarsus, 0.80. 



In the series of 44 adult males examined there is naturally a 

 considerable amount of individual variation in plumage. That 

 affecting the development of the chestnut color on back and 

 breast may be summarized as follows : — 



With no chestnut whatever on back or scapulars. . . 21 



With the back chiefly blue 18 



With the back about equally blue and chestnut. ... 4 



With the chestnut of the breast divided 30 



With the chestnut of the breast continuous anteriorly. . 11 

 Not belonging strictly to either category 2 



In addition to this individual variation in the development of 

 the chestnut there is a very slight one in the shade of the blue, 

 which ranges from almost a 'smalt' hue to rich ultramarine; but 

 the variation in this respect is far less than in either true .S*. mex- 

 icaiza or either of the northern races. 



Unfortunately there are no specimens in Mr. Anthony's series 

 representing either sex in autumn or winter plumage, all his 

 specimens having been obtained during the breeding season. 



1 Average and extreme measurements of wing and tail in 18 adult females are as 

 follows: Wing: Average, 4.13 ; longest. 4.27 ; shortest, 4.00. Tail: Average, 2.62 ; 

 longest, 2.70 ; shortest, 2.45. 



