LARIDZ. ate 
the same manner, and insects, which it catches on 
the wing; and a party of these birds may occasionally 
be seen on a summer evening skimming above the 
meadows in pursuit of winged insects.* 
As I said before, the Arctic Tern is much like the 
Common Tern, more especially in its immature 
plumage; but it may at any age be distinguished 
from that bird by the shortness of its tarsus, which 
in the present species only measures six lines, and in 
the Common Tern is as much as eight lines and a 
half: this appears to be nearly the only distinction 
between the immature birds, unless the dark mark 
along the shoulder of the wing, which I before men- 
tioned when describing the Common Tern, should 
turn out to be a good distinction. In more mature 
birds the under parts are darker than in the Common 
Tern, being almost the same colour as the back. 
The following description of the adult bird is taken 
from a specimen shot at Stolford during the last 
week in April:—the bill is coral-red; irides very 
dark brown; the whole of the upper part of the 
head as far down as to the eye, and the nape of the 
neck are glossy black; the back, scapulars and wing- 
coverts are uniform gull-grey; the rump and tail- 
coverts are white; the primary quills are dusky grey, 
white on the inner part of the inner web, and the 
shafts are white; the tail is much forked, the two 
* © Zoologist’ for 1865, p. 9766. 
