338 Mr. R. B. Sharpe on Saxicola monticola, 



if we could only settle the differences before us by the theory 

 of hybridization instead of by natural sequence of change. 

 For I have always felt that the crossing of birds in a state of 

 nature is a theory that requires the utmost caution in ac- 

 cepting, as it runs the risk of being invoked on every occa- 

 sion where the facts appear to be at all difficult of compre- 

 hension. As regards the conclusions arrived at by the 

 authors of the foregoing paper, I must state that they seem 

 to me incontrovertible. The solution of the question of the 

 changes of plumage in Saxicola monticola was certainly one 

 for a field-naturalist, and it was lucky that three such good 

 observers as our authors should have been led to study this 

 intricate subject. I have carefully gone over the skins of 

 Saxicola monticola in the British Museum, and have tested 

 them with the observations of our authors, with the follow- 

 ing result : — 



Saxicola leucomeljina, Burch. ; Seebohm, Cat. B. Brit. 

 Mus. V. p. 377. 



" b. ? ad. sk. Damara Land (C /. Andersson). R. B. 

 Sharpe, Esq. Type of S. diluta, Bl. & Dr." 



Mr. Seebohm has made a guess at the sex of this specimen, 

 as it has no collector's ticket attached. It is, according to 

 the foregoing observations of Messrs. Butler, Feilden, and 

 Reid, an adult male in the 9th stage. 



" c. c? imm. sk. Dariep (C. /. A.). R. B. Sharpe, Esq.'* 

 A male in the plumage of the adult female, but darker. 

 It is in the first stage of B., F., & R. On the forehead, eye- 

 brow, and chin there is a hoary shade. 



'' d. ^ imm. sk. Hykomkap (C. /. A.). R. B. Sharpe, 

 Esq." 



A young male in moult, apparently changing from its 

 nestling plumage into its first winter dress; the shoulder- 

 feathers slightly edged with hoary whitish. 



" e. S ad. Hykomkap (C. J. A.). R. B. Sharpe, Esq." 

 An adult male in 5th stage of B., F., & R. 



