100 



BULLETIN 86, UNITED STATES NATIONAL MUSEUM. 



one, and the name is tenable even if the assigned tj^pe-locality be 

 erroneous. 



Specimens examined. — Four specimens seen, from the localities 

 below : 



^''Bolivia.'''' ^ — [No further locality specified.] 



Peru. — Lima; Callao. 



Measurements of specimens of Chordeiles acutipennis exilis. 



^ 



2 Used in measurement averages on p. 99. 



CHORDEILES ACUTIPENNIS MICROMERIS, new subspecies. 



Chars, suhsp. — Resembling Chordeiles acutipennis acutipennis, but 

 larger ; upper parts not so dark ; lower surface paler throughout, the 

 chest and jugulum of a lighter brown, the brown bars on posterior 

 portion lighter and somewhat narrower, the white interspaces wider, 

 particularly on anal region; white subterminal bar on rectrices of 

 male averaging wider. * 



Description.— Ty])Q, adult male, No. 213142, U.S.N.M.; Xbac, 

 Yucatan, Mexico, April — , 1910 ; George F. Gaumer ; original num- 

 ber, 289A. Upper parts light brownish gray, with a more or less 

 evident tinge of buff, particularly on the scapulars, and mottled, 

 vermiculated, and irregularly barred with brownish black, the pileum 

 nearly all brownish black, the scapulars more or less solid black 

 medially, the lower cervix duller and more uniform; tail-feathers 

 fuscous, more or less irregularly and rather narroAvly barred with 

 cream buff and whitish, these bars on the upper side of tail much 

 mottled and broken with fuscous ; a much broader subterminal pure 

 white bar; wing-quills fuscous, all but the outer primaries more or 

 less spotted or barred on both vanes with tawny, ochraceous or buff, 

 having also a broad white bar on four outer primaries mostly pos- 

 terior to the tip of the eighth primary; wing-coverts and tertials 

 mottled, spotted, and vermiculated with white and buffy, much lili:e 

 the back; edge of wing along the alula mostl}'^ buffy or creamy white; 

 lores and supraocular region mixed white and blackish brown; au- 

 riculars and postocular region blackish brown, much mixed with, 

 tawny ochraceous, and a little with white; chin buffy grayish, the 

 posterior lateral portion heavily marked with dark brown: cheeks 



^Doubtless from some locality now within the boundary of Chile. 



