2092 BLUE HAWK, OR HEN-HARRIER. 
minor differences are besides observable in the respective sexes 
and states of both; butas those we have indicated are the only 
ones that permanently exist, and may be found at all times, 
we shall not dwell on the others, especially as Montagu’s 
species appears not to inhabit America. We think proper to 
observe, however, that the adult male of Falco cineraceus has 
the primaries wholly black beneath, while that of the F’. 
cyaneus has them black only from the middle to the point ; 
and that the tail-feathers, pure white in the latter, are in the 
former spotted beneath. The female in our species is larger 
than the corresponding sex of the other, though the males in 
both are nearly of equal size; and the collar that surrounds 
the face is strongly marked in ours, whereas it is but little 
apparent in the other. The £. czneraceus has two white spots 
near the eyes, which are not in the /. cyaneus. The young 
of the former is beneath rusty, without spots. Thus slight 
but constant differences are seen to represent a species, while 
the most striking discrepancies in colour, size, and (not in this, 
but in other instances) even of form, prove mere variations 
of sex or age! We cannot wonder at the two real species 
having always been confounded amidst the chaotic indications 
of the present. 
Even Wilson was not free from the error which had pre- 
vailed for so long a period in scientific Europe, that the ring- 
tail and hen-harrier were two species. Though he did not 
publish a figure of the present in the adult plumage of the 
male, he was well acquainted with it as an inhabitant of the 
southern States; for there can be no doubt that itis the much 
desired blue hawk which he was so anxious to procure—the 
ouly land bird he intended to add to his “ Ornithology,” or at 
least the only one he left registered in his posthumous list. 
It was chiefly because he was not aware of this fact, and 
thought that no blue hawk existed in America corresponding 
to the European hen-harrier, that Mr Sabine, in the Appendix 
to Franklin’s “‘ Expedition,” above quoted, persisted in declar- 
ing that the marsh-hawk was a distinct species peculiar to 

