BUBONID^ — THE OWLS. 423 



those of the upper surface more ereseentie. those on the lower tail-eoverts, narrower, 

 and more distant. Tail crossed by five bands, composed of detached transverse spots. 

 Only the face, foreueck, middle of the breast, and feet, are immaculate; everywhere 

 else, excepting on the erissum. the dusky and white are in nearly equal amount. Wing, 

 18.00; tail. 9.80; culmen, 1.10. Wing formula, 3=4. 2-1=5. 



Young (No. 36,434. Arctic America, August, 1863; MacFarlane) : Only partially feathered. 

 Wings and tail as in the adult female described, but the blackish bars rather broader. 

 Down covering the head and body brownish or sooty slate, becoming paler on the legs. 



It is only at irregular intervals, and usually during very severe 

 winters, that this arctic species becomes common in the United 

 States. Such a winter was that of 1876-77, when the Snowy Owl 

 was really abundant along the Atlantic seaboard, as far south as 

 Washington at least, and probably much farther. 



Genus SURNIA Dumeeil. 



Surnia Dumeeh,. Zool. Anal. 1806. 34. Type, Strix ulula Linn. 



Gen. Chab. Size medium; form elongated, and general aspect hawk-like. No ear- 

 tufts. Four outer quills with their inner webs sinuated, the third longest ; tail nearly as 

 long as the wing, graduated. Ear-conch small, simple, oval. Bill strong, yellow. Eyes 

 small, the iris yellow. Tarsi and toes thickly covered with soft, dense feathers; tarsus 

 shorter than the middle toe. Plumage much more compact and less downy, and remiges 

 and reetriees stiller and straighter, than in other owls. 



The single species of this genus belongs exclusively to the cold- 

 temperate and arctic zones of the Northern Hemisphere, and is 

 circumpolar. Though somewhat hawk-like in its appearance, it is 

 nevertheless a true Owl, and possesses no affinities of structure 

 vath the Hawks, any more than other species of Strigiche. 



The two races of S. tilula may be distinguished as follows : 



Common Chaeactees. Above dark vandyke-brown, the head above dotted with 

 white, and the scapulars spotted with the same. Beneath transversely barred with 

 vandyke-brown and white, the bars regular, continuous, and sharply defined. Head and 

 neck with two lateral,, and one posterior median, stripes of brownish black, the space 

 between them with white prevailing. Bill and iris yellow. Wing about 9.00; tail, 6.80-7.00. 



a. ulula. White spotting prevailing. Hah. Paleearctic Eegion; occasional in 

 western Alaska. 



p. caparoch. Brown spotting prevailing. Halt. Nearctic Begion. 



