180 BIRDS OF ILLINOIS. 



make a deep nest, suspended by its upper edge between the forks 

 of a horizontal twig. The eggs are white, generally with a few red- 

 dish or brown blotches. 



"Quite a number are characterized by having the eyes white, 

 red, or yellow." (Hist. N. Am. B.) 



Analysis of Subgenera. 



Vireosylva. Bill compressed, narrow; culmen and commissure straight, the tip ab- 

 ruptly curved (or, if thi- is not the case, there i- no trace of light bands on the wing; ^ee 

 section "&"). Superciliary stripe continued back to the occiput. No trace of light bands 

 on the wing. No conspicuous ring round the eye. 



Lanivireo. Billcompresse !, stout; culmen arched from the base, commissure curved. 

 Superciliary stripe stoppi g at posterior angle of the eye and curving under it, enclosing 

 the eye in a conspicuous orbital ring, interrupted only in front. Two conspicuous white 

 bands on the wing. 



Vireo. Bill stout, scarcely compressed, sub-cylindrical. First primary not spurious 

 or, if so, not acute. 



SUBGENUS Vireosylva BONAPARTE. 



Vireosylva BONAP. Comp. List, 1838, 26. Type, Muscicapa olivacea LINN. 



SUBGEN. CHAB. "Wings long and pointed, one third or one fourth longer thnn the 

 nearly even or slightly rounded tail. First quill very small (less than one third the 

 second), sometimes apparently wanting. Second quill longer than the seventh, much 

 longer than the secondaries. Tarsi short (scarcely extending .60 of an inch) ; toes rather 

 long. Body slender and elongated. Bill slender, narrow, straight ; the culmen straight 

 for its basal half, the commissure quite straight; light horn-color, paler beneath. Feet 

 weik." (Hist. N. Am. B.) 



COMMON CHAEACTBBS. Above plain olive, without distinct wing markings, the pileum 

 more grayish, contrasting more or less strongly with the color of the back; a more or 

 less distinct superciliary stripe of whitish, and beneath it a rather ndistinct dusky streak 

 before and behind the eye. Lower parts whitish, the crissum and axillars. and some- 

 times flanks, yellowish. 



A. First primary rudimentary, usually concealed.* 



* In very rare instances V. olivacea has a well-developed spurious primary, as witness 

 the following, by Mr, Batchelder, in the "Nuttall Bulletin," vol. ii.pp. 97,98: "On Septem- 

 ber 3, 1877, at Bar Harbor, Me., Is! ot a Red- eyed Vireo ( Vireo o livaceus) which is curiously 

 abnormal in having well-developed spurious first primaries, which measure 1.16 inches 

 in length, the wing measuring 3.15 inches. Through the kindness of Mr. J. A. Allen, I 

 have examined the Vireos of this species in the collection of the Museum of Comparative 

 Zoology, and find in a series of about seventy specimens four more cases of the same 

 variation. They are as follows: No. 23,281 (Coll. M. C. Z..from Coalburgh.W. Va.,) with 

 spurious primaries on both wings, measuring 1.17 inches (wing 2.23) ; No. 23,274 (Coll. M. 

 C. Z., same locality), with a spurious primary only on the left wing, measuring 1.10 inches 

 (wing 2.92.) No. 4, 185 (Coll. M. C. Z., from Newtonville, Mass.), with spurious primaries on 

 both wings, measuring 1.09 inches (wing 3.02) ; and No. 4,793 (Coll. M. C. Z., same locality), 

 with a spurious primary on the left wing, measuring 1.15 inches, the wing measuring 3.21. 

 It may be well to say that they are not the first primary coverts, but are true spurious 

 primaries, lying in the same plane as the other primaries, and differing from the spurious 

 primaries of other species of this family only in being somewhat smaller. This variation 

 seems particularly interesting from the fact that the presence or absence of a spurious 

 primary has been to some extent taken as a basis of classification in this family." 



