WHITE- TAILED HAWK. 
379 
nent, that we have hitherto considered them as identical, con- 
trary to the opinion of Vieillot, whose authority, it is true, 
could in this case be of little weight, as he had not seen the 
species, but, like many others, had merely given it a name ; 
his sole knowledge of it being derived from the work of 
D’Azara. We have now yielded only to the decision of Tem- 
minck, (who has lately introduced the young into his Planches 
Coloriees,) but not without much reluctance, especially as that 
distinguished ornithologist has evidently not been at the trou- 
ble of comparing the two species ; otherwise, he would cer- 
tainly not have omitted noticing their affinities and differential 
characters; since in the history of species so closely allied as 
these two, the differential characters are of more importance 
and utility than the most laboured descriptions. 
This comparison we have carefully instituted between our 
American specimens, and others from Africa and Java. They 
agreed perfectly, especially wdth that from Java, in every, 
the minutest character, even feather by feather, much better 
than birds of prey of the same species, and from the same 
country, do generally. They are even more alike than differ- 
ent specimens from the Old Continent of the black-winged it- 
self, since that species is said to vary considerably in the black 
markings, which extend more or less on the wings in different 
individuals. Nevertheless, a constant, though trivial, differen- 
tial character, added to the difference of locality, has induced 
Falco Sonninensis, Lath. Ind. Suppl. p. 12, sp. 38. 
Elanus coesius, Savigny, Ois. dEgyp. p. 98, pi. 2, f. 2. Vieill. Nouv. Diet, 
d'Hist. Nat. viii. p. 240, (now Elanoides.) 
Elanus melanopterus, Leach, ZooL Misc. iii. p. 4. pi. 122. Vigors, Desen 
Austral. Birds, in Tr. Lin. Soc. xv. p. 185. 
Le Blac, Le Vaillant, Ois. d'Afr. i. p. 147, pL 36, male, 37, young male. 
Black-winged falcon, Lath. Syn. Suppl. ii. p. 28. sp. 23. 
Sonnini's falcon. Lath. Syn. Suppl. ii. p. 52. sp. 59. 
The inspection of original drawings, in a collection that Mr Gray, of the Bri- 
tish Museum, was kind enough to show me lately in London, has enabled me to 
add to these already numerous synonyms, Falco axillaris, Lath. Ind, Suppl. 
( Circus axillaris, Vieill. !) from New Holland. 
