70 Mr. J. H. Gurney's Notes on 



coverts, especially the latter, exhibit a considerably larger 

 proportion of fuliginous markings, and a proportionately 

 smaller admixture of fulvous spots, than are to be found in 

 the young of B. erythronotus, in contrast with which there is, 

 however, in the young of B. poliosoimis, a conspicuous nuchal 

 patch of pale luteous, varied by dark brown shaft-marks in 

 the centre of each feather. 



On the under surface the young B. poliosomus is by far the 

 darker bird of the two, except as regards the throat, which is 

 of an equally deep brown in both species. In the first ])lu- 

 mage of B. poliosomus the entire colouring of the underparts 

 of the body is dark fuliginous brown, with the exception of 

 narrow fulvous edgings to the feathers on the throat, of some 

 small fulvous spots on the sides of the breast and abdomen, 

 and of similar but larger spots on the thighs and under tail- 

 coverts. The tail is alike in both species. 



The specimen described by Mr. Sharjie as a " female (? in 

 changing j)lumage) " appears from its dimensions to be more 

 probably a male not fully adult '^; and this circumstance, com- 

 bined with the fact that a very nearly adult male from Chili 

 (in the Norwich Museum) still retains slight rufous tips to 

 some of the feathers on the sides of the neck, leads me to be- 

 lieve that in this species, as in B. erytlironotus, the male as- 

 sumes a plumage resembling that of the adult female, inter- 

 mediately between its first dress and the final stage of its 

 adult coloration. 



I believe that the plumage described by Mr. Sharpe as 

 *' adult " is that of the adult male only, and that the adult 

 female is always rufous ori the back, and more or less so on 

 the under surface also. 



Assuming this view to be correct, the following are the 

 measurements of two males and four females preserved in the 

 Norwich Museum, all of which are either nearly or fully 

 adult : — 



* The "blackish" tint of the slate-coloured parts of the plumage in 

 this specimen is indicative of its not being a fully mature bird, the slate- 

 coloured portions of the plumage being a clear grey iu fully adult birds of 

 both sexes. 



