SUBFAMILY LAEIN^, GULLS. 619 



halluces. It will be seen that the definition excludes all the Xemce, which seem to form 

 a very natural section by themselves, and, among the Larem proper, excludes Rissa, 

 with its naually imperfect hallux ; Pagophila, with its entirely white color and some 

 peculiarities of form ; and the whole group of dark colored, usually red-billed, Gulls, 

 comprising Leacophcena, Blasipm, Adelarus, &c. 



The old genus, Larus, has been, to an entirely unwarrantable extent, subdivided by 

 some late systematists. There being scarcely any appreciable diflerences of form among 

 most of the Lari, these authors have based generic characters upon the colw of the 

 mantle and primaries. But between two extremes of color, e. g. L. marinus and glaiicus 

 (from slaty black to the lightest of pearly or whitish blue), there is found evtry shade, 

 and such features as these should not be made grounds for generic divisions. If it 

 be admitted that the " genera" of Lari typici are quite arbitrary, established to facili- 

 tate the determination and recollection of species, somewhat after the fashion of an 

 index, in which subjects are arranged after some fixed and previously agreed upon 

 order of sequence, their usefulness cannot be questioned, but I do not think that they 

 are natural genera. 



We iind among the Zarl three, perhaps four, groups, the species of each of which are 

 more closely allied among themselves than are those of the dift'erent groups. They 

 may be thus arranged and defined : 



A. " Wlnte-winged GulU." — Of large size, inhabiting exclusively the higher latitudes 

 of the Northern Hemisphere ; with exceedingly light-bluish, sometimes almost white, 

 mantles, and white or bluish primaries, without any black on them ; light yellow biils ; 

 flesh-colored legs. This group constitutes the genus (JZatfcwsof Bruch (1853); Laroides 

 of Brnch (1855) ; Leucus of Bonaparte (1856). AH the well-accredited species are rep- 

 resented in North America. They are three in number — glaums, J^ucopterus, and glau- 

 cescens. 



B. ' ' Black-baclced Gulls." — Of the very largest and medium size, cosmopolitan ; with 

 slaty-black mantles ; primaries crossed with black ; yellowish bills, flesh-colored legs. 

 They again are of two types — a larger, embracing the most powerful known Gulls {ma- 

 rinus, &c.), upon which is founded Bruch's genns Bominicanus ; and a smaller, com- 

 prising L.fuscm and its representative species from various parts of the world, serving 

 as the type of Bonaparte's genus Clupeilarus. 



C. " Herring Gulls." — Of rather large and medium size, cosmopolite ; the quite numer- 

 ous species all having the bill yellowish, with a spot of red at the eminentia ; the legs 

 flesh-colored ; the mantle some shade of blue ; the primaries crossed with black. Upon 

 the type of this section is based Laroides of Brehm. The type is the European Her- 

 ring Gull — argentatvs of Brunnich ; intimately allied species or varieties are, smiih- 

 so«Ja;i«*, Cones ; micAa?irf?estt, Bruch ; occirfeKfaZis, Audubon; (?) 6o)'t'a?is, Brandt. Cali- 

 fornicus, Lawrence, is exactly intermediate between this and the succeeding section. 



D. " Aleic Gulls." — Of medium and small size, inhabiting the Northern Hemisphere ; 

 greenish-yellow bill, not very robust ; bluish mantles ; primaries crossed with black ; 

 legs greenish-yellow, instead of flesh-color. Typical Larus of Linnaeus, comprising 

 delavarensis, Ord ; canus, Linnseus ; brachyrhynchus, Richardson ; and other representa- 

 tive species and varieties. 



The North American species may be tabulated as follows : 



Analysis 0} the North American Lari. 



A. Large and robust : mantle whitish or pale-pearly ; no black on 



primaries at any age. 



a. Mantle very pale; primaries the same, fading insensi- 

 bly into white far from the tips. 



1. Larger : length, about 30 inches ; wing, 18.00 or 



more ; bill and tarsus, each, about 3.00 glaucus. 



2. Smaller: length, about 24 inches; wing, 17 or 



less ; bill, about 2 ; tarsus, 2.25 lbucopterusI 



J. Mantle light blue; primaries the same, with definite 



white tips Giaucescexs. 



B. Very large: mantle slaty-blackish; primaries crossed with 



black; size of the first maeincs. 



C. Large : mantle some shade of blue, darker than in A, lighter 



than in B; primaries crossed with black; feet flesh-colored. 



1. Mantle grayish-blue; bill moderately ro- 



bust -* AKGENTATUS var. smithsonianws. 



2. Mantle slaty-blue; bill very robust.. argestatus var. occidentalis. 



D. Medium and small : primaries crossed with black ; feet dark ; 



webs yellow. 



1. Tarsus obviously longer than the middle toe 

 and claw : bill of adult greenish-yellow, en- 

 circled with a black baud ; first primary 

 usually with a sub-apical white spot ; 

 length, about 18 — 20 inches delawaeensis. 



