1872.] MR. H. E. DRESSER ON SPECIES OF ACIUILA. 803 



in it by the Blackbirds, though, of course, only to be spoilt or 

 broken. I seldom find a nest containing many Blackbirds' eggs 

 without there being some pecked or broken ones amongst them, so 

 that those still entire are often glued to the nest and to each other 

 by the egg-matter spilt over them ; I was therefore all the more 

 glad on finding a specimen so exceptionally clean as this. The eggs 

 in the nest I send differ so much in size and colour that you will 

 perhaps find it difficult to believe them all of one species. I regret 

 very much that when I returned to Buenos Ayres last summer the 

 season was so far advanced that incubation had begun in almost 

 every nest I found ; otherwise I would have sent you half a hundred 

 Blackbird's eggs in order to enable you to see how much they vary. 

 "Besides the Common Blackbird, the only species I positively 

 know to lay sometimes in other birds' nests is the Molothrus badius; 

 but its eggs are very easily distinguished from those of M. bonari- 

 ensis. The eggs of the 31. rufo-axillaris are larger than those 

 of its two congeners, and white without any spots; and I have 

 never yet detected it laying in other birds' nests. I have collected 

 some facts additional to those contained in former letters on the 

 Blackbird, but, as I have sent so much other matter by this mail, will 

 not trouble you with them just at present." 

 " Buenos Ayres, August 6, 1872." 



Mr. H. E. Dresser, F.Z.S., exhibited a large series of skins of 

 Eagles {Aquila), and made the following remarks : — 



" Mr. W. E. Brooks, of Etawah, forwarded to me some time ago a 

 splendid series of Indian Eagles, and requested me to carefully 

 compare them with our European birds, and to report the result. 

 I have also been intrusted with a large series of Eagles from the 

 collections of Canon Tristram, Lord Walden, Lord Lilford, Mr. J. 

 H. Gurney, and Mr. Howard Saunders, together with those from 

 Mr. Brooks, numbering nearly ninety specimens ; and Lord Walden, 

 Mr. J. H. Gurney, and Mr. Blanford have kindly met and carefully 

 examined the series with me, Mr. Gurney and Lord Walden in 

 particular having spent much time in thoroughly investigating the 

 matter. The result at which we have arrived is as follows : 



" Aquila bifasciata, Gray, is, we make out, a perfectly distinct and 

 good species, differing in all stages from Aquila mogilnik. It never 

 attains a dark blackish brown plumage, nor does it assume the white 

 scapulars. It is at all times of an earth-brown colour, varyiuo- i n 

 shade according to age. The tail forms also a fair distinctive 

 character, being but indistinctly barred, whereas Aq. mogilnik has 

 the tail very strongly marbled with dark brown on a greyish ground 

 to two thirds of its length from the base, the remaining third beino- 

 dark brown narrowly tipped with light buff. Aquila bifasciata 

 appears also to have at all stages the upper tail-coverts more or less 

 white, in one specimen almost pure white ; whereas in Aquila 

 mogilnik they are dark, tipped with dull buff. In one example the 

 abdomen is distinctly barred, much the same as in Circaetus gallkus, 

 which I am inclined to think is a very adult bird ; for were this a 



