NATURAL SCIENCES OF PHILADELPHIA. 
131 
(varieties A, &c.) are really the progressive stages of the same individuals. 
I do' not think that even the dusky stage constitutes a distinct “variety,” 
(i.e., the birds remaining in that state all through their lives ;) much less the 
other stages. I am of opinion that every Jager, before arriving at full maturity, 
passes through each of these states : beginning with a rufo-rayed plumage — 
to be presently described — passing from that next into the dusky ; and then 
assuming successively the other stages above characterized. The only ques- 
tion is this : What age, sex, or season is this dusky stage characteristic of ? 
I think that it comes in next after the very young rufo-rayed plumage, for 
this reason. We find these dusky birds to be generally less robust than the 
others; with weaker bills, less elongated central tail feathers, and parti- 
colored tarsi. Now it is well known, that the younger the bird, the smaller 
it is, the shorter are the central tail feathers, and the more yellow the tarsi. 
Another argument, by analogy, is that the S. parasiticus is found in exactly 
the same unicolor state ; and from a great number of species it can be proved, 
I think, that in that species it supervenes directly from the rufo-rayed plu- 
mage. [See remarks under L. parasitica.'] 
The following is the plumage of birds of the year : 
Young of Year. — Bill much smaller and weaker than in the adult, light 
colored to beyond the nostrils, when it becomes brownish-black. Feet and 
toes mostly bright yellow, the terminal portions of the latter black. The 
whole body is everywhere transversely waved with dull rufous. On the head, 
neck and under parts this rufous forms the predominating color ; and the 
bands are exceedingly numerous, of about the same width as the intervening 
dark color. On the flanks and under tail coverts the bars become wider, and 
almost white in color. On the back and wing coverts the brownish black is 
the predominating color ; and if any rufous is present, it is merely as a nar- 
row edging to the feathers. The under wing coverts have irregularly-angular 
transverse waves of brownish black and white. The remiges and rectrices are 
brownish black, darker at their tips ; fading into whitish towards the bases of 
their inner vanes. On the head and neck the light rufous decidedly predomi- 
nates, and seems indistinctly but thickly nebulated with dusky ; this dusky 
forming a conspicuous spot just at the anterior can thus of the eye. (In this 
plumage the bird is the Stercorarius striatus of Brisson and the Larus crepi * 
datus of Ganelin and Latham.) 
There can be no doubt that the Stercorarius striatus of Brisson. and the 
Larus crepidatus of Gmelin and Latham, refer to this species in the very im- 
mature state of plumage just described ; when the bird is considerably 
smaller than when adult, and is wholly rayed with rufous and dusky, with 
white spaces at the bases of the wing and tail feathers. The Stercorarius 
crepidatus of Yieillot, (1817,) however, is the true parasitica, as is also the 
Lestris crepidata, of Degland, 1838, and of Schinz, 1840. The Lestris crepi - 
data of Brehm (1823) is the young of the Buffoni . (Vide synonyms of 
these species.) 
Latham in his Index, page 819, gives a “ Larus crepidatus var. /?,” which 
is of course also to be referred to the young pomarinus. 
The Larus parasiticus of Meyer and Wolf is, I believe, the only instance of 
the application of that specific name to this species. The other synonyms of 
the species do not require any special notice, as they are quite plain and 
uncomplicated. 
By most authors the Catharacta cepphus of Briinnich is considered as refer- 
ring to the long-tailed species. I must confess, however, that I can hardly 
discover grounds for &uch an identification of this name ; and am rather 
inclined to the opinion that his cepplius is based upon the young pomarinus ; 
as are the crepidata of Gmelin and Latham, and the striatus of Brisson. Let 
us look at the description for a moment. It is evident, from almost every 
paragraph of it, that he had in view a young' bird of the year, — in the state 
1863.] 
