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. I agree, however, 

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

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

 Falco melanogenys^ 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 nigriceps. I 

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

 Magellan Straits as 



Falco Cassim, 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 whole 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, 

 uns^iotted ; 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 under 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 with numerous buffy white bars, becoming 

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

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

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

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



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

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

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

 20 inches, culmen 1*35, wing 18"5, tail 7*8, tarsus 1"9. 



Young male. Above deep blackish brown, the na})e tinged 

 with chestnut, all the feathers more or less distinctly margined 



