508 PARTD.^. 



obseiTed which do not i^ossess these stripes*. Such examples 

 certainly may have been visitors from abroad ; but it would 

 seem as though in Scandinavia the amount of white in the 

 plumage generally varies somewhat according to the latitude 

 at which the bird lives, and that specimens from its extreme 

 northern limits are perceptibly whiter than those bred further 

 south. Accordingly, if this be the case in examples from one 

 continuous tract, it would appear only reasonable that still 

 greater variation should be observed in examples from a 

 country which has been cut off from that tract so long as 

 Britain has been separated from the continent. Should, 

 therefore, further research shew that in northern examples of 

 the Scandinavian Long-tailed Titmouse the white of the head 

 encroaches more on the nape or even the mantle, and that of 

 the scapulars and flight-feathers is more extensive than in 

 southern examples, it would be pretty clear that the greater 

 or less proportion of white which any bird of this genus 

 possesses is hardly to be taken as a specific character, even 

 when it is reduced to the small limits presented in ordinary 

 British examples. Again, the Long-tailed Titmouse of Spain 

 has lately been described as a distinct species, and no one 

 looking only at the type-specimen, which has been kindly 

 entrusted to the Editor by Mr. Dresser, would hesitate to 

 declare that its separation was justifiable ; but that gentle- 

 man and Mr. Sharpe in their excellent work state that it is 

 difficult to tell whether some Piedmontese examples are iden- 

 tical with the British or the Spanish form. Thus the matter 

 must be left to the consideration of ornithologists. Those 

 who, like the authorities just named, would recognize as valid 

 four European species of the genus Acrednla, should call the 

 British bird A. vagans (this specific name of Leach's taking 



* Mr. Blyth (Mag. Nat. Hist. ser. 2, i. p. 203) mentions one "in which the 

 black markings on the head were nearly obsolete. " Mr. Hancock's collection 

 contains an example killed in Northumberland with a pure white head, and there 

 is a similar specimen in the Museum of Newcastle-on-Tyne, supposed to have 

 been obtained in that neighbourhood. Mr. Gatcombe also records (Zool. s.s. 

 p. 29i3) his having observed in a flock near Bridgwater in October, 1871, an 

 example with a white head. 



