336 
U. S. V. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT, 
the second quill. The third quill is longest ; the fourth and fifth successively a little shorter ; 
the second a little longer than the sixth, ahout .25 of an inch shorter than the third, much 
longer than the secondaries. The tail is slightly emarginate and rounded. 
The contrast between the ashy of the head and the ashy olive is very little marked, the colors 
not separated by any well defined line. The white stripe on the side of the head is not well 
defined ; anteriorly it has a yellowish tinge ; the dusky of the lore is not very decided. The 
dusky of the lore is continued through, and a little behind the eye. The sides of the neck 
along the throat have rather more yellowish in their brown. There is a brownish tinge in the 
yellowish on the side of the body. The under tail coverts are faintly tinged with yellowish. 
Specimens vary a little in the amount of yellow beneath, which, however, very seldom be- 
comes conspicuous ; it is usually brightest on the abdomen. 
This species is readily distinguished from all the other American Vireos with spurious first 
primary, by the plain colors and absence of pale margins to the outer webs of the quills. 
Some Vireosylvas have no more white in the wings, but these lack the spurious primary. 
While all the specimens of Vireo gilvus from the Eastern States have the proportions of the 
quills nearly as described, all from the Pacific coast (five) agree in having the wings more 
rounded, the third and fourth about equal, the fifth a little shorter, the second about equal to, 
or only a little longer than the seventh, .15 of an inch shorter than the sixth, and .30 
shorter than the third. The bill is smaller, more depressed, and darker above. It is probably 
to a specimen of this bird that Swainson alludes in his article on Vireo bartramii, as having 
been taken on the Columbia river by Douglass, but immature and injured by insects. The 
proportions of the quill are the same, if the spurious quill be taken into the account, which 
would advance his numbers by one throughout, (second and seventh about equal instead of first 
and sixth, &c.) The description, however, is really based on the Brazilian specimen referred 
to, which is entirely distinct. 
Should the western specimens really prove distinct, they may appropriately bear the name of 
Vireo swainsonii. 
List of specimens. 
Catal. 
No. 
Sex. 
Locality. 
When col- 
lected. 
Whence obtained. 
Orig. 
No. 
Collected by- 
Length. 
Stretch 
of wings. 
Wing. 
Remarks. 
1017 
988 
1082 
1016 
1237 
10115 
4729 
5305 
6825 
6826 
5915 
6824 
5521 
9 
3 
3 
3 
May 21,1843 
May 19,18-13 
May 21,1843 
May 24,1843 
5.33 
5.33 
5.67 
5.42 
8.83 
8.92 
9.25 
9.17 
2.83 
2.92 
2.83 
May —,1843 
3 
3 
9 
May 9,1857 
June 15,1856 
5 
4.75 
9 
8 
2.50 
Iris dark brown .... 
Mimbres to Rio Grande. 
5.00 
8.50 
96 
747 
3 
May —,1856 
5.25 
6.08 
