378 
WHITE- TAILED HAWK. 
take, which would be otherwise of more consequence, inasmuch 
as no one else could, for a long time, detect it. This species 
resembles, it is true, S, celata, (whose range must remain 
limited to the Rocky Mountains,) and perhaps still more S» 
ruhricapilla, Wilson, but it is not of the same subgenus, Dacnisy 
and it may readily be known by the white spots of the tail 
feathers. 
When the genus Sylvia^ containing upwards of tw’o hundred 
and fifty species, shall have been properly studied, it will be 
found practicable to divide it into several more sections, sub- 
genera, and even perhaps genera. This bird, along with many 
other North American species, will constitute a highly natural 
group, very distinct from the true Sylvia^ of which S. atrica-- 
pilla may be considered as the type. We presume that it is 
the group we have in view, to which Mr Swainson has given 
the name of Sylvicola^ in his Synopsis of Mexican birds. Our 
species is erroneously placed by Buffon among his JOemi-finSj 
corresponding to our Dacnis, and Wilson’s Worm-eaters. 
WHITE-TAILED HAWK.—FALCO DISPAR Plate XI. Fig. ]. 
Falco dispar, Temm. et Laug. PI. Col. 319, young female. Noh. App. to Synopsis 
of N. A. Birds in Ann. Lyc. New York, p. 435. — Milvus (now Elanoides) leu- 
curus, Vieill. (Alcon bianco, d’Azara) Nouv. Diet. d'Hist. Nat. xx, p. 556. — 
Falco melanopterus, Noh. Jour. Ac. Ph. v. p. 28. Id. Cat. Birds U. S. sp. 
16. in Contr. JHacl. Lye. i. p. 11. Id. Synopsis of N. A. Birds, sp. 16, in Con. 
Bye. N. Y. — Le Faucon blanc, Sonnini's d'Azara, iii. p. 96, sp. 36. — My Col- 
lection. 
ELANUS DZSPJ^.— Jardine. 
Falco dispar, Bonap. Synop. App. p. 436. 
This beautiful hawk, which we recently discovered to be 
an inhabitant of North America, is so strikingly similar to the 
black- winged hawk [Falco melanopterus^) of the Old Conti- 
Falco melanopterus, Daud. Orn. ii. p, 152, sp. 12T. Lath. Ind. SuppL 
p. 6. sp. 16. ’ 
