764 SYSTEMATIC SYNOPSIS.— LONGIPENNES— GAVIZ. 
Wings comparatively shorter than those of hirwndo, being absolutely a little shorter, though 
forsteri is a larger bird; very light colored, being strongly silvered; outer web of the first 
primary is not black, but silvery like the others; all the primaries want the very decided white 
space on the inner webs which exists in hirwndo and macrwra ; there are indications of it on 
the three or four outer primaries, but the others are a nearly uniform dusky gray, moderately 
hoary. Entire under parts white, with scarcely a trace of the plumbeous so evident in 
hirundo, and so decided a color in macrura. Tail a slightly lighter shade of the color of 
the mantle, separated from the latter for a short space by the decidedly white rump; lateral 
feathers much more lengthened than in hirwndo, the elongation generally quite equalling that 
of macrura, and sometimes even exceeding it. These two lateral feathers are white on the 
outer web, dusky-gray on the wner. This being exactly the reverse of hirwndo, and a very 
noticeable feature, was the first to draw attention to the bird; and this character being so 
tangible and convenient, writers have perhaps laid too much stress upon it, to the exclusion 
of others quite as evident. Feet bright orange, tinged with vermilion ; tarsus shorter than 
middle toe and:claw ; feet longer and stouter by over 0.10 of an inch than the same parts in 
hirundo. Adult, winter plumage: The black of the bill increases so much that nearly the 
whole bill becomes dusky, except a small space at the base of the under mandible, and a 
terminal space of varying extent. The feet lose their vermilion tinge and become dusky 
yellowish. The black pileum more or less variegated with white on forehead; but there 
is always considerable black left on the nape, and a more or less broad and distinct bar 
always extends along the sides of the head, embracing the eyes. The lateral tail-feathers 
have not the elongation and attenuation of those of summer, being but little, if any, longer 
than those of hirundo during the breeding season. The color of the inner web is usually 
darker, and sometimes extends on the outer as well as the inner, especially toward the tip of 
the feather. (S. havelli Aud.) At the time of the moult the old primaries -lose their 
silvering and become plain brown and white, their shafts being of a decided yellow. The 
inner webs at this season have white spaces, with nearly as distinctly defined margins as are 
found in hirwndo and macrura. Young: Bill in all its proportions considerably smaller and 
weaker than that of the adults; brownish-black, fading into dull flesh-color at base of under 
mandible. Front white, but the crown and nape show traces of the black that is to appear, 
which is now mixed with light brown. Pearl-blue of back and wing-coverts interrupted by 
irregular patches of light grayish-brown, showing a tendency to become transverse bars; this 
grayish-brown on the tertials deepens into brownish-black, and occupies nearly the whole 
extent of each feather. The primaries differ from those of the adult in having less silvery 
gloss, and the inner white spaces more marked, being in fact like those of the adult hirundo. 
Rump and under parts pure white. The tail intensifies, so to speak, its adult characters as 
regards color; and, independently: of any other feature, will always serve to identify the 
species. It is deeply emarginate, but the lateral feather is not greatly produced, surpassing 
the second by scarcely more than the latter surpasses the third. Its inner web, for an inch or 
so from the tip, and both webs of the other feathers, grayish-black ; the intensity of this color, 
and also its extent, decreasing successively on each feather from without inward, so that the 
central pair scarcely deepen their color at the tips. The outer web of the lateral feather white, 
but sometimes is just at the tip invaded by the darker color of its inner web. N. Am. at large, 
common ; breeds from Texas to the Fur countries; abundant along Atlantic coast during the 
migrations; S. in winter to Brazil. Nest in marshes; eggs 2-3, 1.85 X 1.35, yellowish-drab, \ 
freely but irregularly spotted and dashed with different shades of brown. 
799. S, macru'ra. (Gr. paxpés, makros, long; otpd, owra, tail.) Arctic Tern. Adult in 
breeding plumage: Bill shorter than head, equal to middle toe and tarsus together, slender, 
compressed, acute, deep carmine, or lake red; usually without any black, but this color 
sometimes appearing in a limited degree. Feet remarkably small and weak; tibia bare for 
