NATURAL SCIENCES OF PHILADELPHIA. 
545 
Diag. — S. Sternse Mrundini similis : sed rostro longiore, valdb robustiore, tarsis 
longioribus, validioribus ; cauda magis producta, perlacea, rectrice lateral! 
pogonio interno fusco-griseo, extern© albo. 
Habitat. — Very extensively distributed over North America. Atlantic Coast 
and Gulf of Mexico. Fur countries. Great Lakes and Rivers. Texas. Utah. 
California. 
In view of the considerations presented in the two preceding articles, it may 
be well to look somewhat carefully into the characters of the present species. 
Adult , spring plumage. — Bill orange-yellow, black for nearly its terminal half, 
the extreme points of both mandibles yellowish; robust,* deep at the base ; 
culmen markedly declinato- convex, eminence at symphysis well developed ; in 
total length from one to two-tenths of an inch longer than in S. hirundo. The 
black pileum does not extend so far down on the sides of the head as it does in 
hirundo , barely embracing the eye (the lower lid of which is white), and leav- 
ing a considerably wider white space between the eye and commissural edge 
of superior maxilla than in hirundo. The color of the back hardly differs ap- 
preciably from that species ; it is perhaps a shade lighter. The wings are com- 
paratively considerably shorter than in hirundo , being absolutely a little less, 
though Forsteri is a larger bird. They are very light colored, being strongly 
silvered with the peculiar hoariness common to most of the species of the 
genus ; this lighter color is very observable even on the coverts. The outer 
web of the first primary is not black, but silvery like the others ; all the prima- 
ries want the very decided white space on the inner webs which exists in hirundo 
and macroura ; there are indications of it, indeed, on the three or four outer 
primaries, but the others are a nearly uniform dusky-gray, moderately hoary. 
The entire under parts are white, with scarcely a trace of the plumbeous 
which is so evident in hirundo , and amounts to so decided a color in macroura. 
The tail is a slightly lighter shade of the color of the mantle, separated from 
the latter for a short space by the decidedly white rump. The lateral feathers 
are much more lengthened than in hirundo , the elongation generally quite 
equalling that of macroura , and sometimes even exceeding it. These two 
lateral feathers are white on the outer web, dusky-gray on the inner. This 
being exactly the reverse of hirundo , and a very noticeable feature, was the first 
to draw attention to the bird, and this character being so tangible and coqve- 
nient, writers have perhaps laid too much stress upon it, to the exclusion of 
others, quite as evident and more important. The feet are bright orange, 
tinged with Vermillion ; the tarsus shorter than the middle toe and claw ; the 
feet longer and stouter, by over GO of an inch, than the sames parts in hirundo. 
When the primaries become old, i e., at the approach of the spring or autumn 
moult, before the species begins to put on its complete summer or winter livery, 
the primaries lose their beautiful silvering, and become plain brown, their 
shafts inclining to decided yellow. They have then also distinct white spaces on 
their inner webs, nearly as well marked as in hirundo or macroura. 
Adult , winter plumage. — The bill loses the bright orange-yellow which exists 
in summer, the black encroaching upon it, so that it becomes almost wholly 
dusky. The base of the under mandible in dried skins appears as if it might 
have been flesh-colored in life. The feet also lose their bright color, and in- 
cline to a dusky-yellowish. The black pileum is more or less mixed with 
white, the white predominating on the forehead so as to leave it nearly pure ; 
there is always considerable black left on the nape, and also a broad band on 
the side of the head, embracing the eye, and reaching to the nape behind, ex- 
actly as represented in Audubon’s plate of S. Havelli. The long lateral taiL 
feathers become greatly shortened, so as to be but scarcely, if at all, longer 
than those of hirundo during the breeding season. The color of the inner webs 
becomes darker, though it does not extend so far towards the base of the feather; 
sometimes it invades the outer web also, towards the tip. 
Young of the gear, before the first, moult. — -Bill every way considerably smaller, 
1862 .] 38 
