362 Mr. J. H. Giirney's Notes on 



two sexes of this species are both those of male birds. Two 

 females from Natal, acquired by the British Museum subse- 

 quently to the publication of Mr. Sharpe's volume, measure 

 9*7 and 9*9 inches respectively in the wing, and 2"75 in the 

 tarsus, which, so far as I have observed, is about the usual 

 length of these parts in female specimens of this Hawk. 



The late Dr. Dickerson* obtained at the Zambesi an un- 

 usually large adult female of S. tachiro, which was decidedly 

 paler in its coloration throughout than is the case in ordinary 

 specimens. I have recently examined this skin, which is pre- 

 served in the Norwich Museum, and I do not consider that 

 the pale colour is due (as might be supposed) to the plumage 

 being in a faded or worn condition. 



The allied Abyssinian race, S. unduliventer (Riipp.), though 

 not separated by Mr. Sharpe from S. tachiro, is readily dis- 

 tinguishable when adult by the richer rufescence of the flanks 

 and transverse pectoral bars : this race extends westwards to 

 Senegal ; and an adult female from Casamanze in the Norwich 

 Museum is the type oiAstur tibialis, Verr., which must there- 

 fore sink into a synonym of S. unduliventer ; this specimen 

 measures 9*5 inches in the wing and 2"8 in the tarsus ; but a 

 female in the British Museum, from Shoa, is slightly smaller, 

 measuring 8*55 in the wing and 2" 7 in the tarsus. 



The Hawk from the Cameroons in Captain Shelley's col- 

 lection, from which Mr. Sharpe took his description of Astur 

 tibialis, is probably the immature plumage of some other 

 species, which is apparently at present unnamed. 



Since the publication of Mr. Sharpe's volume, the British 

 Museum has obtained from the river Danger a Hawk 

 which may prove to be a still younger example of the same 

 species as that in Captain Shelley's collection ; if so, the 

 latter would seem by its dimensions, which are given by Mr. 

 Sharpe, to be a male, and that from the river Danger to be 

 a female, as it measures 8*8 inches in the wing and 2*6 in the 

 tarsus ; this specimen is less rufous on the underparts than 

 Captain Shelley's bird, though showing traces of that tint on the 

 breast and flanks ; its thighs, instead of being rufous, as in the 

 * Vide Ibis, 18()8, p. 144. 



