224 NORTH AMERICAN BIRDS. 



narrow, obliquely vertical, with the upper end the posterior one. (Sub- 

 family Falconincv.') 

 c'. Nostril circular; cutting-edge of upper mandible with a strong tooth- 

 like projection, separated from the strongly booked tip by a distinct 



notch Falco. (Page 244.) 



c'. Nostril linear, obliquely vertical, the upper end posterior to the lower; 

 cutting-edge of upper mandible without distinct tooth or notch. 



Polyborus. (Page 253.) 



rt'. Outer toe reversible ; claws all of the same length, narrower and rounded on 



under side Pandion. (Pago 254.) 



Genus ELANOIDES Vieillot. (Pago 222, pi. LXV., fig. 1.) 

 Species. 



Head, neck, entire lower parts (including under wing-coverts and basal half of 

 secondaries, underneath), and band across rump, pure white ; back, wings, and tail 

 plain polished blackish; tertials white, with blackish tips. Adult: White of head 

 and neck immaculate ; back, scapulars, and lesser wing-coverts with a soft velvety 

 gloss of dark bronzy purplish, the other black portions with a glaucous or chalky 

 cast. Young : Head and nock narrowlj' streaked with dusky ; the black of back, 

 etc., less glossy, more brownish, and with greenish instead of bronzj- purple reflec- 

 tions; quills, tail-feathers, and primary coverts narrowly bordered at tips with 

 white. Length 19.50-25.50, wing 15.40-17.70, outer tail-feathers 12.50-14.50, cul- 

 mcn 0.70-0.80, tarsus 1.00-1.30, middle toe 1.00-1.20. Nest in tops of tall trees, 

 usually near watei'-courses. Eggs 1-4, 1.85 X 1-46, white or buffy white boldly 

 spotted or blotched, chieflj' round larger end, with hazel-brown, chestnut, or rich 

 madder-brown. Hab. Tropical and warm-temperate portions of continental 

 America, north in the interior rcgularlj' to Iowa, Minnesota, Illinois, etc., along 

 Atlantic coast casually to Pennsylvania and southern New England ; accidental in 

 England 327. E. forficatus (Linn.). Swallow- tailed Kite. 



Genus ELAN US Savignt. (Pago 222, pi. LXV., fig. 2.) 



Species. 



AihiJt : Above plain pale bluish-graj', becoming gradiudlj- white on head and 

 tail, with a large patch of uniform deep black covering lesser wing-covert region ; 

 lower parts entirelj' pure white ; a black spot in front of and partly surrounding 

 ej'e. Young : Somewhat like adult, but tinged with rust}*, and with indistinct 

 dusky streaks, on upper parts, the wing-feathers narrowlj' tipped with white ; tail 

 with an indistinct subterminal band of duskj- ; breast stained, or indistinctly 

 blotched or streaked, with yellowish rusty. Length 15.15-16.75, wing 11.50-13.30, 

 tail 5.90-7.40, culmen .65-.80, tarsus 1.20-1.50. Nest on trees, near water. Eggs 

 3-5, 1.65 X 1-32, handsomely marbled or clouded with vai-ious shades of rich mad- 

 der-brown on a paler (sometimes whitish) ground. ILib. Tropical and subtropical 



