32 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



men, and under tail-coverts white or pale g'ra3dsli (sometimes dis- 

 tinctl}^ grayish), usually more or less streaked, narrowly, with dark 

 sooty gray, the under tail-coverts often sooty gray margined with 

 white; axillars and under wing-coverts dark sooty gray, the coverts 

 near edge of wing growing more or less distinctly margined with 

 white; bill, iris, and feet as in adult male; length (skins), 171-201 

 (182.7); wing, 136-147 (112.3); tail, 68-75 (70.9); exposed culmen, 

 10-13 (11.7), width of bill at frontal antia% 8-10 (8.6); tarsus, 11.5-16 

 (15.1); middle toe, 15-17 (16.1); depth of fork of tail, 14-20 (17.3). « 



Immahire male {second year). — Exactly like the adult female in col- 

 oration. (Older specimens have admixture of gloss}^ blue-black 

 feathers on the under parts, the black feathers usually appearing first 

 on the throat.) 



I)nmature female {second year). — Similar to the adult female, but 

 upper parts less strongly glossed wdth steel blue, this confined princi- 

 pallv to the posterior half of the pileum and the scapular region, the 

 general color of the upper parts Ijeing dark sooty, or grayish l)rown; 

 feathers of anterior under parts more distinctly margined with whitish, 

 and remaining under parts more decidedly and uniformly white. 



« Twenty -seven specimens. 



Specimens from different geographic areas average as follows: 



Localitv. 



MALES. 



Eight adult males from Virginia to New 

 York 



Five adult males from Mississippi Valley. 

 Ten adult males from Florida (mostly, if 



not all, breeding birds) 



Ten adult males from Arizona 



Two adult males from western Texas 



One adult male from Guadalajara. Me.xico 



(breeding) 



FEMALES. 



Eight adult females from Virginia, Mary- 

 land, etc 



One adult female from Iowa 



Ten adult females from Florida (mostly 

 breeding) 



Four adult females from Arizona 



One adult female from western Texas 



Three adult females from Guanajuato, 

 Mexico (breeding) 



Wing. 



145.6 

 149.3 



144.3 

 147.6 

 144.5 



142.9 

 142 



140.5 

 143.4 

 143 



Tail. 



Ex- 

 posed 

 culmen. 



Width of 

 bill at 

 frontal 

 antise. 



11.6 

 11.7 



72.9 11.3 



74.1 11.9 



72. 2 12 



71.9 

 70 



70.9 

 70.2 



71 



11.5 



11.6 

 11.5 



11.6 



12 



12 



8.4 

 9 



8.2 

 8.7 



8.4 

 9 



8.6 



8.5 

 8.5 



Depth 



of fork 



of 



tail. 



18 

 19.1 



18.6 

 19.1 



18 



17.3 

 17 



17.2 



17.8 

 20 



I am not able to make out any well marked or constant variation coincident with 

 faunal area among specimens from the extensive region indicated by the above table 

 of measurements, although it is barely possiljle that a more adequate series, com- 

 posed chiefly of adult females taken at localities where they unquestionably breed, 



