Mr. R. B. Sharpens Catalogue of Aocipitres. 451 



The following are my measurements of the specimens just 

 referred to : — 



Males, ascertained or presumed. 



Wing. tarsus. middle toe s. «. 



in. in. in. 



A not fidly grown 2-00 2-00 



E 12-50 2-00 1-90 



G 12-15 1-90 1-80 



n 12-10 1-90 1-90 



J 1205 200 1-70 



Females, ascertained or presumed. 



B 14-30 2-10 205 



C 13-70 2-10 2-15 



D 13-80 2-15 2-10 



F 13-80 2-05 1-95 



I 13-60 2-10 2-00 



The scarce Australian G. hypoleuca, to which I propose 

 now to refer, like the other Falcons which I have included 

 in the subgenus Gennaia, has, when immature, the central 

 pair of rectrices entirely free from the transverse bars, the 

 other rectrices being at that age less distinctly barred than 

 in the adults. The immature plumage, which is not de- 

 scribed by Mr. Sharpe, may also be recognized by the greater 

 length and breadth of the shaft -marks on both the upper 

 and the under surface, some of the latter assuming the ap- 

 pearance of ovate spots, especially towards the flanks ; the 

 nape is also tinged with cream-colour in the young plumage, 

 with dark terminal spots on the nuchal feathers ; and the grey 

 of the mantle is then more or less tinted with pale brown. 



The specimen described by Mr. Sharpe as " adult " appears 

 to me to be passing from immature to adult dress ; in the 

 fully adult bird the central rectrices have numerous and dis- 

 tinct transverse bars of dark grey with interspaces of pale 

 grey, as shown on the figure of this Falcon in Gould^s ' Birds 

 of Australia ' ; in an old female preserved in the Norwich 

 Museum these bars are twelve in number. 



The measurements of G. hypoleuca given by Mr. Sharpe 

 appear to me to have been taken from a very short-winged 

 male. I annex the dimensions of a presumed male and three 



