334 REVIEW OF AMERICAN BIRDS. [PART I. 



Female birds generally similar, but smaller. 



(No. 1,418, % .) Fresh specimen : Total length, 6.33 ; expanse of wings, 

 10.25 ; wing from carpal joint, 3.33. Prepared specimen : Total length, 5.75 ; 

 wing, 3.20; tail, 2.50; difference between 1st and 2d primaries, .17, of 5th 

 and 2d, .10, of 9th and longest, .86 ; length of bill from forehead, .70, from 

 nostril, .42, along gape, .85 ; tarsus, .77 ; middle toe and claw, .t5, claw alone, 

 .20 ; hind toe and claw, .48, claw alone, .21. 



In No. 1,418 the second quill is longest, the third and fourth a 

 little shorter ; the first or outer a little less than the fourth, muich 

 longer than the fifth. In other specimens the first quill is longer 

 than the fourth ; generally, it may be said, that the first quill is 

 always (or with rare exceptions) nearly equal to the fourth, some- 

 times a little longer, sometimes a little shorter ; always much longer 

 than the fifth, the second quill always longest of all. 



There is some variation in color in this species, both individual 

 and seasonal. In No. 34,081, %, from Iowa, the colors are purer 

 and brighter ; the ash of crown dark and clear, without the olivace- 

 ous wash so frequently met with. The dusky markings about the 

 head are almost black, and there is almost no yellowish whatever on 

 the crissum. 



Autumnal and late summer specimens are much more brightly 

 colored ; the olive clearer, the gray of head more sharply defined, 

 and the crissum and axillars with a strong tinge of yellowish. In 

 only a single spring specimen out of twenty is there a positive, 

 though still pale sulphur yellow crissum, all others showing this 

 faintly or not at all. The most brightly colored autumnal skin in 

 the series is No. 22,308 (Washington, October), in which the colors 

 are nearly as vivid as in V. chivi, and perhaps answering to V. 

 virescens of Vieillot.^ 



There is considerable difference in thickness, and some in the length 



' In the article on Vireonidse, in the Paeiflo R. R. Report, page 333 (Birds 

 N. America) I have given the name of V. virescens, Vieillot, to the Bartraniian 

 Vireo, V. agilis. In this, however, I am now satisfied I was wrong. The 

 specific name was based by Vieillot (Nouv. Diet. d'Hist. Nat. XXXVI, 1819, 

 104) on a bird killed in New Jersey. He describes the top of the head as 

 " blackish ;" the figure, however, distinctly represents a black line bordering the 

 crown, and above the light supra-ocular stripe. The quills and tail feathers 

 are said to be edged with greenish, the lower tail coverts to be yellowish, the 

 length 4.60. Nothing is said about the proportions of the quills. In view 

 of all the circumstances, locality, etc., it is very probable that this description 

 belongs to a young, perhaps autumnal V. olivacea, a name apparently unknown 

 to Vieillot. There is no indication in the description of the very bright colors 

 of V. chivi or agilis, the olive being described as having a strong giayish tinge. 



