168 MR. H. SAUNDERS ON THE LARIN.E. [Feb. 5, 



Larus smithsonianus, Coues, Pr. Ac. N. Sc. Philad. 1862, p. 296 

 (North America). 



In this species the amount of white on the primaries increases with 

 the age of the individual. Mr. Dresser (B. of Europe, xxii. L. ar- 

 gentatus, p. 3) describes an adult male from the Orkneys in summer, 

 in my collection, as having " the outermost primary almost entirely 

 blackis-h, white towards the tip, and crossed by a subapical black 

 band ; the next two grey at the base, black towards the tip, being 

 finally terminated by a large white spot." This is correct, so far 

 as any breeding bird with unspotted pearl-grey mantle may be termed 

 adult; but the example in question is far from being an old bird. 

 Bearing in mind that the extreme white tip diminishes by abrasion 

 with the age of the feather, the following are the patterns of the 

 outer primaries with the increasing age of the bird : — On the outer 

 primary the white spot, or " mirror," absorbs the black bar till the 

 latter wholly disappears, leaving the primary pure white from the 

 tip to more than two inches upwards ; whilst from above, a grey 

 " wedge " along the inner web gradually eats into the black portion, 

 reducing the width of the black along the inner web to only two 

 inches. In the second primary a white "mirror" appears, which 

 also increases with the age of the bird ; but in this feather, so far 

 as I have yet seen, it does not wholly absorb the black bar and 

 unite with the white tip ; what it does, however, is to eat round the 

 black above it, so as to cut off the black from the inner web, and 

 thus unites with the grey wedge, which has been gradually increasing 

 its dimensions downwards. It is needless to give a minute description 

 of the remaining primaries; it will suffice to say that, as a rule, the 

 encroachment of the light portions upon the dark ones increases with 

 the age of the bird, and there may easily be stages of further pro- 

 gression with which I am not yet acquainted. This grey " wedge " 

 on the upper portions of the primaries should be borne in mind, as 

 it is an important distinction between some closely allied species. 

 These observations equally apply to the Yellow-legged Herring-Gull 

 (L. cachinnans) and to the American bird which Dr. Coues formerly 

 distinguished as L. smithsonianus. Dr. Coues, although he has 

 given it up as a species, even now maintains (B. of N.W. Am. p. 628) 

 tliat if a subapical spot (or " mirror") is present on the second pri- 

 mary of the American bird, it is small ; but in two examples before 

 me, of the correctness of whose locality I am well assured, the one 

 from Grand Mauan, in June, has it well developed, whilst in another, 

 from Long Island, the mirror extends right across the feather, and 

 on the inner web has nearly eaten through the black and effected a 

 junction with the grey wedge above. Indeed only one European 

 bird in my collection has the mirror still more developed. The 

 average of American may possibly be a little larger than the average 

 Old-World specimens ; but I have not examined a sufficient series of 

 the former to speak with the same confidence upon this point that Dr. 

 Coues does ; at any rate that difference is admittedly unworthy of 

 specific distinction. The mantle in the true adult L. argentatus is, 

 as every one knows, pearl-grey, the legs and feet being flesh- 

 coloured ; and the ring outside the eye is of a pale ye/low. Taking 



