BIRDS OF NORTH AND MmDLE AMERICA. 621 



b. Nostril a large oval or roundish opening at anterior end of cere, the latter not 

 inflated, except (sometimes) laterally; pteryla of pileum arranged in longi- 

 tudinal row8.<* 

 c. Tail much less than two-thirds as long as wing, truncate or slightly rounded; 

 tarsus much more than one-ninth as long as wing; length of cere on top 

 more than half as long as chord of culmen. 

 d. Longer under tail-coverts, falling far short of tip of tail; bill mostly exposed, 

 claws wholly so; color not white. 

 e. Smaller (wing not more than 200 mm., usually much less); cere inflated 

 laterally. 

 /. Without ear-tufts; tarsus with much more than lower half naked (some- 

 times wholly so) Gymnasio (p. 676). 



ff. With ear-tufts; tarsus with not more than lower half naked, urfually 

 feathered to base of toes (even the toes sometimes feathered or bristled) 



Otus (p. 681). 

 ee. Larger (wing 230-475 mm.); cere not inflated laterally. 

 /. With conspicuous ear-tufts. 



g. Fifth, sixth, and seventh, & primaries longest, the tenth (apparent 

 outermost) not longer than secondaries; ear-tufts composed of rela- 

 tively longer and narrower feathers; toes entirely naked; bill and 

 feet relatively much weaker; size smaller (wing about 300 mm.). 



Lophostrix (p. 732), 



gg. Seventh, eighth, and ninth c primaries longest, the tenth much 



longer than secondaries; ear-tufta composed of relatively shorter 



and broader feathers; toes feathered (except terminal phalanges); 



bill and feet relatively much stouter; size larger (wing 350-475 mm.) . 



Bubo (p. 736). 

 ff. Without ear- tufts. 



g. Toes feathered (except terminal phalanges); bill and feet relatively 



much stouter, the former less compressed Pulsatrix (p. 754). 



gg. Toes completely naked; bill and feet relatively much weaker, the 



former more compressed Ciccaba (p. 759). 



dd. Longer under tail-coverts reaching nearly if nojt quite to tip of tail; bill and 

 claws mostly hidden by long bristle or hair-like feathers; color v hile 

 (more or less barred or transversely spotted with slate color). (Size 



oiBubo) Nyctea (p. 767). 



cc. Tail much more than two-thirds as long as wing, graduated; taraus less than 

 one-ninth as long as wing (shorter than middle toe, with claw); length of 



cere on cop less than half as long as chord of culmen Sumia (p. 772). 



hb. Nostril a small circular opening near middle of the inflated (semibulbous) cere; 



pteryla of pileum uniformly and thickly feathered. 



r. Seventh and eighth, or sixth, seventh, and eighth, «i primaries longest, the 



tenth (apparent outermost) shorter than second « (sometimes shorter than 



first);/ tarsus slightly if at all longer than middle toe with claw; outer toe 



only slightly shorter than inner toe; smaller (wing less than 120 mm.). 



a This last character assumed as to Lophostrix, Bubo, Pulsatrix, Ciccaba, Nyctea, 

 and Sumia. 



b Fourth, fifth, and sixth from outside. 



c Second, third, and fourth from outside. 



d Third and fourth, or third, fourth, and fifth from outside. 



« Ninth from outside. 



/ Tenth from outside. 



