312 
U. S. P. R. E. EXP. AND SURVEYS — ZOOLOGY— GENERAL REPORT. 
In examining an extensive series of specimens I find some differences which may be of 
importance. Thus, in the Columbia river specimens the entire back and scapulars are nearly 
pure uniform green, with the faintest possible wash of purplish brown. The feathers on the 
rump are purplish violet, slightly glossed with green. In 6625, from the Copper mines, the 
back is purplish brown, with only a trace of green ; the rump nearly pure bluish green, with 
the merest trace of violet. In a specimen from Agua Nueva the colors are much as in the last 
except that the purplish brown is more confined to the scapulars and the middle of the back, as 
in the Columbia river specimens. The wing is longer than in any I have seen, (4f inches.) 
In one specimen from Tejon Pass, apparently immature, the tertials are terminated broadly 
with pure white. 
The female differs in the much less brilliancy of color, especially that on top of head and 
rump, the former more brown. The under parts are dirty white. 
List of specimens. 
Catal. 
No. 
Sex and 
Locality. 
When col- 
lected. 
Whence obtained. 
Orig'l 
No. 
Collected by— 
Length. 
Stretch 
ofwings. 
Wing. 
Remarks. 
3954 
3955 
6024 
6025 
6965 
6966 
6026 
1895 
1945 
5914 
6027 
6028 
6029 
3 
3 
9 
3 
Q 
Q 
o 
3 
3 
3 
3 
3 
Q 
Spring of 1853. 
229 
230 
5.00 
5.00 
12.00 
12.00 
4.75 
4.75 
Eyes dark br'n ; bill 
black ; feet light 

Medicine Bow C'k, Neb. 
Bridger's Pass, Utah.... 
July 25, 1857 
July 29, 1857 
Lt. F. T. Bryan.... 
do 
330 
354 
July 12,1835 
Steilaooom, W. T 
June — , 1855 

5.00 
12.25 
Dr. Suckley, U. S.A. 
110 
43 
45 
do... 
Mar. 1, 1854 
Aug. 3, 1854 
COTYLE, Boi 
Cotyle, Boie, Isis, 1822, 550. (Type H. riparia.) 
Ch. — Bill very flat, extremely broad at the base, and gradually narrowed towards the tip ; nostrils prominent and rounded. 
Tail moderate, nearly straight or somewhat emarginated. Tarsi rather shorter than the middle toe, slender and scutellated. 
Toes very slender, the claws slightly curved. Colors generally dull brown above, without gloss. 
This genus is distinguished from Hirundo by the slightly forked tail, rather long tarsi, very 
slender toes, and extremely dull colors. The two United States species are the smallest we 
have. Each will form the type of a special division, of at least sub-generic value, with the 
following characters : 
Cotyle, Boie.— -Tarsi with a tuft of feathers near the toes, on the posterior face. Edges of 
outer primaries normal. 
Above grayish brown ; beneath white, with a well defined pectoral band G. riparia. 
Stelgldopteryx, Baird. — Tarsi naked. Edge of outer primary with the fibrillae converted 
into a series of stiffened recurved hooks. 
Above light sooty brown ; the under parts brownish ash, fading behind into white. 
S. serripennis . 
