LARIDA —STERNINA:: TERNS. T65 
14.50 inches; extent about 31.00; wing from the carpus 10.50; tail 6.00; depth of fork 3.50 
(average) ; bill along culmen 1.35 ; height at base 0.33; from feathers on side of lower man- 
dible to tip 1.60; gonys 0.80; gape 2.10; tibie bare 0.50; tarsus 0.80 to 0.85 ; middle toe 
0.75, its claw 0.30; outer 0.70, its claw 0.18; inner 0.48, its claw 0.14; hallux with its claw 
0.28; whole foot about 1.75. Extreme range: length 13.00 to 16.00; extent 29.00 to 32.00; 
wing 9.75 to 11.75; tail 5.00 to 7.00; tarsus 0.66 to 0.875; bill 1.25 to 1.50. Females average 
a little less than the males. Young fall under the above minima; length down to 12.00, wing 
to 9.00, tail to 4.00, bill to 1.12, ete. Young-of-the-year in August: Upper mandible brown, 
| becoming blackish on the culmen toward the tip, and somewhat flesh-colored basally along 
' the tomia. Under mandible light yellow, darkening into brown toward tip. Mouth yellow; 
feet dull yellow, with searcely a tinge of reddish. Forehead grayish-white; on the vertex this 
gray intermixed with large, roundish, illy-defined spots of blackish ; on occiput and nape black 
is the prevailing color, the extreme tips of the feathers only beg gray; on sides of head, as 
far as eyes, the black also nearly pure. The ground-color of the upper parts is a rather lighter 
shade of the pearl-blue of the adults, but every feather is tipped with dull light gray, and has 
a subterminal spot (generally a crescent or semicircle) of light brown. These spots and tips 
are quite conspicuous, and give perhaps the predominating color to the upper parts ; but they 
are not so distinctly defined, nor so dark, as in macrura. Lesser wing-coverts along the edge 
of the fore-arm form a continuous band of nearly pure brownish-black. Lesser and median 
coverts are conspicuously tipped with yellowish-gray ; greater secondaries, however, fade into 
nearly pure white at their tips. The secondaries are white, with the outer web, except at tip, 
and the median portion of the inner web, dark plumbeous or 
ashy-gray. Primaries colored almost exactly as in the adults. 
Rump white, with a tinge of pearl-blue. Tail slightly forked, 
the emargination being but little more than an inch; inner 
webs of all the rectrices nearly pure white, but the outer webs 
are plumbeous-gray, increasing in intensity from within out- 
ward; so that the outer pair of rectrices, which are but little 
tapering or elongated, have their outer webs grayish-black, 
deepest toward their tips. Entire under plumage, including 
the under wing-coverts, pure white, with no trace of the 
plumbeous wash of the adults. The winter range and changes 
of plumage of this familiar species are not well known; it 
does not appear to lose the black cap, which nevertheless is 
imperfect at that season. North America at large, Europe, 
ete. Breeds and winters variously in its N. A. range. 
Eggs 3, 1.65 X 1.25, not distinguishable from those of allied 
species. 
8. S. for/steri. (To J. R. Forster. Figs. 50, 516.) ForstTr’s 
TERN. Similar to the last; larger; bill longer, stouter ; 
wings shorter, tail longer; feet longer. Length about 15.00; Fic. 516, — Tail of Forster’s Tern, 
extent 30.00; wing 9.50-10.50; tail 5.00-8.00, forked 2.50— bout # nat. size. (From Elliot.) 
5.00; bill along culmen 1.50-1.75, averaging 1.60, its depth at base 0.40; tarsus 0.90-1.00 ; 
middle toe and claw 1.00-1.10; whole foot averaging 2.00. Adult, spring plumage: Bill 
orange-yellow, black for nearly its terminal half, the extreme points of both mandibles yellow- 
ish ; robust, deep at base ; culmen declinato-convex, eminence at symphysis well developed ; 
length from 75 to ;2,-of an inch longer than that of S. hirwndo. Black pileum not extending 
so far down on sides of head as in hirwndo, barely embracing eye (the lower lid of which is 
white), and leaving a wider white space between the eye and edge of superior maxilla than 
in hirvndo. The color of the back hardly differs from that species ; perhaps a shade lighter. 
