182 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvii. 



ASIO MAGELLANICUS PALLESCENS (Stone). 

 Bubo virginianus pallescens Stoxe, Amer. Nat., XXXI, 1897, ji. 237 (in text). 



Chars. Mihsp. — Like Aslo magellanicus mayensis, but larger, with 

 relatively smaller bill; upper surface paler. 



Type locality. — Watson Kauch, Medina River, 18 miles southwest of 

 San Antonio, Texas. 



Geographical distrihutioii. — Western Texas to southeastern Califor- 

 nia; south to northern Mexico. 



Measu7'ements {9 males). — Wing, 330-300 (average, 311) mm.; tail, 

 195-226 (average, 215.9) ram.; exposed culmen, 33-39 (average, 37.3) 

 mm.; culmen without cere, 24-29.5 (average, 27.3) mm. {9 fcinaleK.) — 

 Wing, 355-375 (average, 362.8) ram. ; tail, 200-235 (average, 222) mm. ; 

 exposed culmen, 35-43 (average, 39) nnu.; culmen without cere, 26-31 

 (average, '1\^) mra. 



The present subspecies, by reason of its much smaller size and 

 nuicli paler colors throughout, is so very dili'erent from virg/iuanus 

 that for typical specimens no comparison is necessary. It seems to 

 reach its greatest degree of pallor in Arizona and the immediately 

 contiguous region. A specimen from Rodriguez, Nuevo Leon, jVIexico, 

 somewhat approaches , virginianus., though not strongly enough to 

 warrant its reference to that form. 



In Asio Til. pal/esce?)s there is, in almost any locality, a remarka))ly 

 wide range of variation, irrespective of altitude or other influences 

 sometimes supposed to be potent in producing such differences in this 

 group of birds; for, in tine, this race exhibits to a marked degree the 

 dichromatism existing in many of the others. The ordinary or light 

 phase in its extreme manifestation is almost as white below as Asio 

 111. iv((jM(C)if/i)/, with legs and feet as immaculate, and is sometimes even 

 paler above, though of course on account of small size not to be con- 

 fused with that form. The dark phase is of very different appearance, 

 the color abo^'e being very blackish, the lower parts dark, with mark- 

 ings l)lackish instead of brownish, the feet ochraceous and nuicli 

 mottled, thus to some degree resembling the similar condition of both 

 occidoifalix <ni(i irapacuih h^ yet rather more ochraceous. There is also 

 a third phase which comes close to the light phase of virginianus., and 

 in which ochraceous predominates throughout tiie plumage of both 

 upper and lower i)arts, including the face and feet. The type of palles- 

 cens is intermediate between the ochraceous and the light gray phases. 



Specimens examined are from the following localities: 



Arizona. — Tucson; Colorado River at Monument 204, Mexican 

 Boundar}' Line; San Bernardino Ranch; Fort Lowell; Camp 98, 

 Kennerl3^and Mollhausen; Fullers; Oracle; Fort Whipple; Huachuca 

 Mountains; Phoenix. 



JVeic Mexico. — San Luis Mountains; Chico Springs; Longitude 107° 

 15', Mexican Boundarv Line. 



