WAEBLING VIREO. 301 



isfaotoiily, I find that ia all of the numerous North American genera examined, those of 

 ten primaries show but one of these little feathers, while the rest have two. In the 

 family Alaudidce, as in Vireonidw, some geuera have ten primaries, others apparently only 

 nine ; and in our genus Eremophila, in which only nine are developed, there are two of 

 the little feathers just mentioned, the overiying one beiug exactly like cue of the pri- 

 mary coverts, the other, though not very similar, more resembling an abortive primary. 

 Alauda arvensis, which shows a minute but obvious spurious quill, has but one such 

 little feather ; and in Galerita eristata, with a spurious quill about two-thiids of an inch 

 long, there is likewise but one. In Clamatorial Passeres, perhaps without exception, 

 there are ten fully developed piimaries, the first of which may equal or exceed the next 

 in length ; and in the single North American Clamatorial family, Tyratinidoe, I hud, as 

 before, only one of these little leathers. In a Woodpecker, remarkable among Pioariau 

 birds for possessiug only nine long primaries, the first being short or apurious, there is 

 also but one. 



It thus seems to be established that amoug supposed nine-primaried birds, the addi- 

 tional one, making ten in all, is normally represeated by the second one of these tiny 

 quills which overlie the base of the outermost fully developed feather ; it being the same 

 little quill which in ten primaried Oscines, in Clamatores, and probably other birds, comes 

 to the front and constitutes the first regular primary, either remaining quite short, when 

 it is the so-called "spurious" primary, or lengtheuiog to equal or excee^ the ocner pri 

 maries in extent. 



It becomes an interesting question whether both of these minute quills be not rudi- 

 mentary primaries, as one of them certainly is. I have failed to detect any material 

 diiference between the two in size, shape, or position. One overlies the other, indeed, as 

 a covert should a primary, bat the two are together inserted side by side on the upper 

 side of the first fully developed quill ; both are rigid and acuminate, more like primaries 

 than like coverts, and boih are abruptly shorter than the true primary coverts. So far, 

 all the evidence favors the supposition that both are rudimentary primaries. On the 

 other hand, coloration is against such hypothesis, as in the original case of Vireoflavi- 

 frons, in which Baird determined the underlying one of these two little feathers to be 

 the missing primary, mainly because it was colored like the primaries, the overlying one 

 resembling the coverts in coloratioa. But the color test is often inapplicable, coverts 

 and primaries being usually like each other in this respect, and color sometimes points 

 the other way. ihus, in Sitta caroUnensis, a ten-primatied Oscine with spurious first 

 primary, the single remaining little feather is white at base across both webs, like the 

 primaries, the true primary coverts being white only on the inner web. 



ViEEO GILVUS (V.) Bp. 

 "Warbling Vireo. 



Vireo gihus, Kirtland, Ohio Geolog. Surv., 1838, 183, 180 — Read, Fam. Visitor, iii, 1853, 

 383; Proc. Phila. Acad. Nat. Soi., vi, 1853, 3'J5.— Wheaton, Ohio Agric. Eep. for 

 1860, 364 ; Keprint, 1861, 6 ; Pood of Birds, etc., Ohio Agric. Eep. for 1874, 565 ; 

 Eeprint, 1875, 5. — Langdon, Cat. Birds of Gin., 1877, 7. 



Vireosylvia gilvus, Langdon, Eevised List, Jouru. Gin. Soo. Nat. Hist., i, 1879, 174 ; Ee- 

 print, 8, 



Warbling Vireo, Ballou, Field and Forest, iii, 1878, 136. • 



Musoieapa gilva, Vikillot, Ois. Am. Sept., i, 1807, 65. 



