768. 
769, 
7710. 
LARIDZA —LARINZ: GULLS. - 741 
Smaller: length about 24.00 inches; wing 17.00 or less; bill about 2.00; tarsus 2.25 lewcopterus 769 
Mantle light blue; primaries the same, with definite white tips . glaucescens 770 
Mantle very pale blue, as in leucopterus; primaries with slate-gray mar. kings . . . . kumlient T10a 
B. Very large: mantle slaty-blackish ; primaries crossed with black; size of the first . . marinus 171 
C. Large: mantle some shade of blue, darker than in 4, lighter than in 8; primaries crossed with black. 
Mantle grayish-blue ; bill moderately robust ; feet flesh-colored bac ons or smithsonianus 772,173 
Mantle slaty-blue; bill very robust; feet flesh-colored . . : . occidentalis 774 
Mantle dark grayish-blue; bill moderately robust; feet yellow; ‘oyeaiig orange + cachinnans 775 
Mantle dark slate; bill moderately robust; feet flesh-colored. . . afinis 776 
D. Medium and small: primaries crossed with black; feet dark-greenish; was yellow. 
Tarsus obviously longer than the middle toe and claw; bill of adult greenish-yellow, encircled 
with a black band; first primary usually with a sub-apical white spot ; length about 18.00-22.00 
delawarensis 778 
Tarsus little if any longer than middle toe and claw; bill with a red spot, but an imperfect black 
band, if any; first primary usually with the end broadly white; length about 20.00-22.00 
californicus TIT 
Tarsus little if any longer than the middle toe and claw; bill slender, greenish, without a black 
band or red spot ; size very small ; length 16.00 or 18.00 a canus or brachyrhynchus 779, 780 
II. Tail and under parts darkin adult. Head white; bill and feet reddish. (Blasipus.) 
Back slaty-lead color bs . . . F heermanni 781 
L, glaucus. (Gr. yAavxds, glaukos, Lat. glaucus, bluish.) GLAUCcOUS GULL. IcE GuLL. 
Bureomaster. Very large: length about 30.00; extent 60.00; wing up to 18.50; bill 2.75- 
3.00 (chord of culmen), along gape 3.75, its depth opposite nostrils 0.80, at angle 0.85 ; tarsus 
3.00-3.25 ; middle toe and claw 2.75. No black anywhere at any age. Adult ¢ 9: Bill large 
and strong, very wide, but not so deep at angle nor so convex at end as in marinus, about as 
long as middle toe and claw; chrome yellow, the tip diaphanous yellow, a vermilion spot at 
the angle. Legs and feet pale flesh-color or yellowish. Iris yellow. Primaries entirely white, 
or palest possible pearly-blue, fading insensibly into white at some distance from their tips, their 
shafts straw-yellow. Mantle very pale pearl-blue. Otherwise, wholly white. In winter: 
Head and hind neck lightly touched with pale brownish-gray. An immature stage: Entirely , 
white; bill flesh-colored, black-tipped. Young: Bill flesh-colored, black-tipped; plumage 
impure white, mottled with pale reddish-brown, sometimes quite dusky on the back; under 
parts a nearly uniform pale shade of brownish ; quills and tail imperfectly barred with the same. 
Smaller: wing 17.50; bill 2.40; tarsus 2.40, ete. Northern and Arctic seas, cireumpolar ; 8. 
in winter in N. Am. to the Middle States, coastwise ; breeds only in the high north. This is one 
of the very largest and most powerful birds of the whole family, fully equalling L. marinus in 
these respects. 
L. leucop’terus. (Gr. Aeuxds, leucos, white; mrepdv, pteron, wing.) WHITE-WINGED GULL. 
Precisely like the last, but smaller. Length 24.00, rather less than more; wing 16.00-17.00 ; 
bill along culmen 1.75-2.00, along gape about 2.75; depth at angle 0.65; tarsus 2.00-2.25, 
not longer than middle toe and claw. This counterpart of L. glaucus inhabits the same north- 
erly regions, coming south to the same degree in winter. It appears to be much less character- 
istic of N. Am. than of Europe. 
L. glauces/cens. (Lat. glaucescens, growing bluish.) GLAUCOUS-WINGED GuLL. Like a 
herring gull with the black of the primaries washed out; primaries of the color of the mantle 
to the very tips, which are occupied by definite small white spots; the Ist also with a large 
white sub-terminal spot. Bill long and rather weak, the upper mandible acute and projecting 
“considerably beyond tip of the under, the convexity near the end comparatively slight ; angle 
pretty well defined, the outline between it and the tip about straight. Tarsus rather longer 
than middle toe and claw. Length about 27.00; wing 16.75; bill along culmen 2.25; 
gape 3.25 ; depth at angle 0.70; tarsus 2.60; middle toe and claw 2.50. Adult in summer: 
Bill light yellow, an orange spot at angle of lower mandible, and a dusky one just above. 
Mandible pearl-blue, much the same shade as in argentatus. Primaries scarcely darker than 
the back, all with well-defined, rounded apical spots of white. First, the base not appreciably 
