110 BULLETIN 86, UNITED STATES NATIONAL MUSEUM. 



or barred on both vanes with tawny, ochraceous or buff, having also 

 a broad white bar on four outer primaries mostly posterior to the 

 tip of the eighth primary ; outer primaries slightly edged or spotted 

 on outer web with buff; wing-coverts and tertials mottled, spotted, 

 and vermiculated with wliite, buff, and ochraceous buff, much like 

 the back; edge of wing along the alula mostly buffy or creamy 

 white; lores and sui)raloral region mixed white, buff, and dark 

 brown ; auriculars and postocular region blackish brown, much mixed 

 with tawny, ochraceous, buff, and a little with white; chin buffy 

 gray, with posteriorly heavy markings of dark brown; cheeks and 

 sides of neck dark brown, much spotted and streaked with ochra- 

 ceous, buff, and whitish; a large triangular patch on throat white; 

 below this a band of dark brown much spotted with ochraceous 

 buff; breast dark brown, finely mottled and vermiculated with pale 

 brownish; rest of lower surface ochraceous buff, paler (buff) on 

 lower breast, with conspicuous dark brown cross-bars, these nar- 

 rower, farther apart, and somewhat broken on lower tail-coverts; 

 lining of wing deep ochraceous buff, barred with dark brown. 



Iris dark brown. 



Measurements. — Female: Total length (in flesh), 203-223.5 (aver- 

 age, 210.1) mm. ; ^ extent of wing, 485-^97.8 (492.8). ^ 



Male:- Wing, 171.5-184.5 (average, 176.2) mm.; tail, 99-115 

 (107.1) ; exposed culmen, 4.9-6.5 (5.7) ; tarsus, 12.5-14.5 (13.5) ; mid- 

 dle toe, 13.2-15.1 (14). 



Female: =^ Wing, 165-177 (168.1)mm.; tail, 99-105 (102.3); ex- 

 posed culmen, 5.0-6.0 (5.4) ; tarsus, 12.1-13.7 (13) ; middle toe, 

 12.5-14.8 (13.7). 



Type-locality. — ^Triunfo, Lower California, Mexico. 



Geographical distrihution. — ^Lower California. Breeds in the 

 Upper Tropical, Lower Austral, and Upper Austral zones, south to 

 San Jose del Cabo and Cape San Lucas; and north to La GruUa, 

 Santa Cruz, and Valladares in the San Pedro Martir region of the 

 northern part of the peninsula. Winters in extreme southern Lower 

 California. 



Remarhs. — The juvenal plumage is similar to that of Chordeiles 

 acutipennis acutipennis, but the lower parts average paler; and the 

 upper surface is lighter, more uniform, more silvery, and less heavily 

 mottled with blackish or dark brown. In the color of the upper parts 

 it is strikingly like the first autumn stage of Chordeiles virginianus 

 howelli,^ but is lighter, more silvery, and usually less mottled with 

 dark brown or blackish. 



^ Three specimens. 



2 Ten specimens, from Lower California, Mexico. 



2 Nine specimens, from Lower California, 



* See p. GO. 



