BIBDS OP NOETH AND MIDDLE AMERICA. 



41 



immaculate white, the longer under tail-coverts usually showing 

 slender shaft-lines of dusky; axillars and under wing-coverts uniform 

 deep sooty gray; bill black; iris brown; legs and feet blackish or 

 dusky brown; length (skins), 152-197 (165.3); wing, 128-141 (133.6); 

 tail, 60-74 (66.5), forked for 11.5-19.5 (16.1); exposed culmen, 9-12 

 (10.9); width of bill at frontal antise, 7-10 (8.2); tarsus, 12-15 (13.6); 

 middle toe, 13.5-15.5 (14.7)." 



Adult female. — Similar to the adult male, but the steel-blue gloss of 

 upi ^r parts less continuous (the forehead and at least anterior portion 

 of c -own always sooty), usually less brilliant and less violaceous; chin 

 and throat usually paler gray, sometimes very pale gray or grayish 

 white, with basal (mostly concealed) portion of feathers deeper gray; 

 length (skins), 144-176 (164.5); wing, 128-137 (133.3); tail, 54-69 (64.1), 

 forked for 9-16 (12.7); exposed culmen, 10-11.5 (10.5); width of bill at 

 frontal antise, 8-9 (8.3); tarsus, 13-14 (13.6); middle toe, 14-16 (14.6).* 



throat being of the latter color. Such specimens show a marked approach to P. 

 dominicensis, and clearly indicate the common origin of the two forms. No examples 

 with more than a trace of steel blue on the under parts (and this on the sides of the 

 breast, or also along sides and flanks, shown in two specimens — one from Duenas, 

 Guatemala, and the other from the Isthmus of Panama) are found among the Mexi- 

 can and Central American series examined, but one from Napo, eastern Ecuador 

 (no. 55333, U. S. Nat. Mus. collection), has the sides of the head, the chest, sides, 

 and flanks, nearly uniform steel blue. 



« Thirty specimens. 



b Eleven specimens. 



Specimens from different localities average, respectively, as follows: 



