Mr. R. B. Sharpens Catalogue of Accipitres. G7 



scription of the adult ; the slaty black of the breast without 

 any whitish tips to the feathers, and extending down to the 

 extremities of the under tail-coverts, and over all the inter- 

 mediate parts except the thighs, but intermingled on the ab- 

 domen with a few mottled feathers of two shades of grey, 

 and with the under tail-coverts inconspicuously tipped with 

 grey ; the thighs clothed with mottled grey feathers, which, 

 for the most part, resemble those interspersed amongst the 

 black plumage of the abdomen ; but in some of them the mot- 

 tlings have ah'eady begun to assume the arrangement of the 

 transverse markings with which, in the succeeding stage, all 

 the tibial feathers are barred, in common with the remainder 

 of the under surface except the chest. 



In the succeeding stage the bird bears a remarkable general 

 resemblance in its coloration and markings to its somewhat 

 more northern and much scarcer ally, Leucopternis princeps. 



In very old males of Geranoaetus melanoleucus (and pos- 

 sibly in old females also ; but of this I am not sure) the trans- 

 verse bars of grey entirely disappear from the whole under 

 surface, except the wing-linings, the flanks where covered by 

 the wings, and the under tail-coverts ; in such specimens the 

 portions of the plumage from which these bars have disap- 

 peared are then pure white. 



I think that Mr. Sharpe is mistaken in stating that the 

 white tips to the grey feathers of the breast are " the remains 

 of immaturity,'^ as I have met with them in very old indi- 

 viduals, and do not recollect having ever seen an adult speci- 

 men in which they were absent ; in some adult examples these 

 white tips are to be found on several of the interscapulary 

 feathers as well as on the breast. 



I may add that those portions of the upper surface in the 

 adult bird Avhich Mr. Sharpe describes as black are all slightly 

 tinged with slate-colour ; so that they may perhaps be more 

 correctly described as " slaty black " than as " black " simply. 



To return to the genus Tachy trior chis, Mr. Sharpe, fol- 

 lowing the late Dr. Kaup, separates under this title two species, 

 Buteo albicaudatus and B. abbreviatus ; but as I greatly doubt 

 whether these tAvo species really follow each other in natural 



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