SUBFAMILY LARIN^, 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 Larcce proper, excludes liissa, 

 with its usually 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 Leucopluius, Blasiims, Adelarus, &c. 



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

 some late sj^stematists. There being scarcely a)iy appreciable difl'erences of form amon?T 

 most of the Ixtri, these authors have based generic characters upon the color of tlie 

 mantle and j^ri^Mirics. But between two extremes of color, e. g. L. iHarivus and glaticits 

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

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

 be admitted that the "genera" of Lari tyinci 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 find among the Lari three, perhaps four, groups, the species of each of which are 

 more closely allied among themselves than are those of the dittereut groups. They 

 may be thus arranged and defined : 



A. " JVhite-winged Gulls." — 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 constitntes the genus Glaucns of Bruch (1853) ; Laroides 

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

 resented in North America. They are three in number — glaucus, leucopterus, and qlau- 

 cescens. 



B. '^ Blacl -hacked 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 genus Dominicanus ; and a smaller, com- 

 prising L. fitscus 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 emiuentia; the legs 

 flesh-colored ; the mautle 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 — argentaftis of Briinnich ; intimately allied species or varieties are, smith- 

 sonianus, Coims ; michahellesii, Bruch; occidentalis, Aadnhou ; (?)6on'a/is, Brandt. Cali- 

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



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

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

 legs greeuish-yellow, instead of flesh-color. Typical Larus of Linna>us, comprising 

 dclawareusis, Ord ; canus, Linnieus ; hrachyrhynchus, Eichardsou ; aud other representa- 

 tive species and varieties. 



The North American species may be tabulated as follows : 



Analysis oj the North American Lari, 



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



primaries at any age. 



a. Mautle very pale; prinuiries the same, fading insensi- 

 bly into white far from the tips. 



1. Larger: length, about l>0 inches; wing, 18.00 or 



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



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



less ; bill, about 2 ; tarsus, 2.25 leucopterus. 



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



white tips GLAUCESCEXS. 



B. Very large: mantle slatj'-blackish ; prinjaries crossed with 



black ; size of the first M,VRLNUS. 



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



than in B; ])rimaries crossed with black; feet flesh-colored. 



1. Mantle grayish-bhie; bill moderately ro- 



bust ,. AiJGKNTATiTS var. smithsouianus. 



2. Mantlt! slaty-blue; bill very robust.. ai!(;kntatus var. occidentalis. 



D. Medium aud small : i)rimari<'s crossed with black; feet dark; 



webs yellow. 



1. Tarsus obviously longer tluiu tlie luiddlo toe 

 and claw ; bill of adult greenish-yellow, ern- 

 circli'd with a black band; first primary 

 usually with a sub-a]>ieal white spot ; 

 length, about 18—20 iuchcs 1)i:l.vwakensis. 



