RARER BRITISH BIRDS. 
55 
ARCTIC JAGER. 
Lestris Parasiticus. Linnaeus. 
There can be little doubt that the bird, figured by Bewick, 
under the name of Arctic Gull, is the Lestris Richardsonii of 
Swainson. Many facts concur to confirm this opinion, particu- 
larly the woodcut, which is that of a bird in the adult plumage, 
in which state, in L. Parasiticus of Linnaeus, the two centre 
tail feathers exceed the other tail feathers in length nearly 
seven inches, while, in L. Richardsonii, the same feathers only 
exceed the rest by three inches. 
The length of both species is about twenty-one inches. Sup- 
posing, therefore, Bewick’s bird to be the true L. Parasiticus, the 
two centre tail feathers ought to exceed the others, in length, 
about one-fourth the whole length of the bird, measuring from 
the tip of the bill to the tip of the centre toe, which, it is evident, 
is not the case. 
Bewick’s account of his bird also agrees with that of L. 
Richardsonii, but not with that of its congener. He mentions 
