700 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



STREPTOPROCNE ZONARIS MEXICANA Ridgway. 

 MEXICAN COLLARED SWIFT. 



Similar to S. z. albicinda, but averaging decidedly larger, general 

 color much duller (less bluish) black, and forehead always distinctly 

 grayish sooty; similar also to S. z. zonaris,"' but averaging smaller 

 and coloration less uniform, the forehead and chin always distinctly 

 paler than rest of head. 



Adults {sexes alike). — General color plain black or sooty black 

 above, slightly more sooty below and decidedly more so on fore- 

 head, chin, and throat, interrupted by a conspicuous collar of white 

 (this broadest on chest), the feathers of this white collar dark sooty 

 brown or dusky basally; bill black; iris dark browTi; legs and feet 

 dusky (more or less livid in life ?) . 



Immature. — Similar to adults, but white collar more or less broken 

 by larger dusky central areas to feathers (especially on chest), and 

 (in younger specimens) feathers of chin and upper throat streaked, 

 those of lower throat tipped with whitish, and those of breast and 

 abdomen and marginal under wing-coverts terminally margined with 

 whitish. 



Young. — Much duller in color than adults, the under parts graj^ish 

 sooty anteriorly, dark sooty posteriorly; white collar developed only 

 on hiudneck (where feathers are rather narrowly tipped with white), 

 the feathers of chest very narrowly margined terminally with white; 

 otherwise like the immature stage, described above. 



Adult maZe.— Length (skins), 183-225 (206.5); wing, 200-215 

 (206.4); tail, 66.5-81.5 (75.6); exposed culmen, 8.5-10.5 (9.6); 

 tarsus, 20.5-24 (22.3); middle toe, 14.5-16.5 (15.2). « 



Adult female.— Length (skins), 187-222 (207); wing, 194.5-206.5 

 (200.5); tail, 62-79 (72); exposed culmen, 9-10.5 (9.8); tarsus, 

 20.5-24 (22); middle toe, 14-16 (15).'' 



« Of southern Brazil and Argentina; see p. 697. 



b Fourteen specimens. 



