of the Magellan Straits. 221 



species if he had had adults, while he might have been easily 

 misled by the rufous character of the young birds into sup- 

 posing that the two birds are identical. 1 agree, however, 

 with Mr. Gurney in supposing that the Magellan bird is a 

 distinct species, being, in fact, the American representative of 

 Falco melanogenysj from which it differs not only in its 

 slightly larger size, but in the less rufous plumage of the 

 female ; and neither male nor female has the very narrow 

 closely set bars of the Australian Falcon, though they are 

 more narrowly barred than the true Falco nigricejjs. I 

 propose, therefore, to separate the Falcon of Chili and the 

 Magellan Straits as 



Falco Cassini, sp. n., 



and append a description of the bird. 



Adult. Above dark bluish ashy, everywhere transversely 

 spotted or barred with' black ; bars very broad and closely set 

 on the upper part of the back, further apart and more sagittate 

 in shape on the lower back, rump, and upper tail-coverts ; a 

 frontal line tinged with whitish, very indistinct ; entire head 

 and hind neck, cheeks, ear-coverts, and moustachial streak 

 (that is to say, the tvhole of the face) deep black, extending on 

 to the interscapulary region ; least wing-coverts blackish like 

 the latter, the others coloured and barred like the back ; quills 

 deep brownish black, the primaries with obsolete grey spots 

 near the base, the inner secondaries uniform with the back ; 

 tail bluish ashy, with black bars, which become merged 

 towards the tip of the tail, so that this is conspicuously black 

 for about a quarter of its length ; throat itself creamy buff, 

 unspotted ; fore neck and chest pale bufFy fawn-colour, with 

 very narrow black shaft -lines, the shade of fawn extending 

 slightly on to the breast ; rest of the mider surface creamy 

 white, with a very strong grey shade on the lower parts, 

 crossed with closely set bars of black ; under wing-coverts 

 buffy white, thickly crossed with black bars ; the inner web 

 of the quills Avith numerous buify white bars, becoming 

 smaller and more obsolete towards the tips of the quills ; bill 

 orange at the base, inclining gradually to bluisli horn-colour 

 towards the tip ; feet yellow, claws horn-brown. Total length 

 15'5 inches, culmen 1*1, wing 12, tail 7, tarsus 2. 



Female. Similar to the male, but larger, and without the 

 bluish shade on the lower parts (probably not so old a bird) ; 

 the head, neck, and sides of the face black. Total length 

 20 inches, culmen 1*35, wing 13*o, tail 7'8, tarsus 1*9. 



Young male. Above deep blackish brown, the nape tinged 

 with chestnut, all the feathers more or less distinctly margined 



