Arpi:>'i)rx n. 



119 



specimens of M. guerilla in tlie collection of Messrs. Salvin 

 and Godman and in the Norwich Museum : — 



For the sake of further comparison, I may add the follow- 

 ing measurements, which I have taken from seven well- 

 marked, but unsexed, specimens of M. ruficoUis : — 



The immature plumage of M. guerilla is subject to con- 

 siderable individual variation, some young birds showing a 

 conspicuous white or yellowish- white nuchal collar, which in 

 many others is more or less imperfect, and in a few almost 

 imperceptible. The extent of the cross-barring on the uuder- 

 parts also varies greatly : in many specimens it extends over 

 the whole under surface of the body, in others it is partially 

 absent, and in a few almost entirely so ; when present, the 

 bars are always further apart than in the adult birds. 



