NOVITATES ZOOLOGICAE XXII. 1915. 185 



the length of the various primaries is different. This statement, however, seems to 

 be confused, and b}' some unfortunate accident it became differently confused and 

 (juite misleading in Vog. il. pal. Fauna ii. p. 1069. I there said that in two adult 

 and one young Falcon from West Siberia I found the first primary at least as long 

 as the third, which is perfect nonsense, as it should have read : Fourth not shorter, 

 but at least as long as first primary! In half a hundred Falcons from Greenland 

 and Iceland this character was not found once, while I found it in two adult females 

 and one young bird from West Siberia, though another young one does not show it. 

 This peculiarity forbids me to unite " uralensis " (.' including ifrebnitzkii) with the 

 Greenland or Iceland form. In colour the two adult females closely resemble adult 

 Icelanders and differ from Norwegian Gyrfalcons (rusticolas) in having whiter heads 

 and being cross-barred with whitish, not pale grey, on the upperside. 



With regard to the Scandinavian race, Falco rusticolus niaticolus L., I cannot 

 understand why it should be treated as specifically, and not subspecifically, distinct 

 from the other northern Falcons. Some specimens, even sometimes fully adult 

 birds, are by colour not with certainty distinguishable from Icelanders or adult 

 Greenlanders ; but they are constantly smaller. As a rule the crown is darker, and 

 they are always darkish, never white. 



I am therefore convinced that I am right in treating all northern Falcons as 

 subspecies of one species, as there is no proof that two forms nest in the same 

 country. But more material must be collected of the Siberian form or forms. 



For further details see \'d<f. pal. Fauna p. 1064 ff. I have not included among 

 the races of F. rusticolus the Falco altaicus (Menzbier), as I am by no means sure 

 that it belongs there. Nothing definite can be said about it until more specimens 

 are available for study. 



