118 VIKEONID^, VIREOS. GEN. 53. 



six genera and nearly seventy recorded species, of which about five-sixths appear 

 to be genuine. The tj'pical and principal genus, Vireo, containing nearly thirty 

 species, is especially characteristic of North America, though several species occur 

 in the West Indies and Central America ; one genus and species, Luletes osburni, 

 is exclusively "West Indian ; the rest — Gyclarlds, HylojMhcs, Vireolanius, and 

 Neocliloe — are, with one exception. South and Central American. In further illus- 

 tration of the characters of the group, I oflfer some remarks under the head of the 

 only genus with which we have to do in the present connection. 



53. Genus VIREO Vieillot. 



The numerous species of this genus have been divided into several groups, but 

 no violence will be done by considering them all as Vireo — in fact, it is difficult to 

 do otherwise. For even the seemingly substantial division into two genera, ac- 

 cording as there is an evident spurious first primarj^ or apparently none, separates 

 species, like gihms and pldladelphicus, hardly otherwise specifically distinguishable ; 

 while another division into two genera, according to shape of the wings and length 

 of the spurious lirst primary or its absence, is subject to some uncertainty of deter- 

 mination, and unites species, like olivaceus and flavifrons, most dissimilar in other 

 respects. The fact is, that almost every single species of Vireo has its own peculiar ' 

 form, in shape of bill, proportions of primaries, etc., and these details cannot well 

 be considered as of more than specific value. These slight differences are perfectly 

 tangible and surprisingly constant, and render the deter- 

 mination of the species comparativelj' eas}^, though these 

 birds bear to each other a close general resemblance in 

 size and color. They are all more or less olivaceous 

 ■^^'^^^^^■^^ '^ above, sometimes inclining to graj^ or plumbeous, with 

 '' the crown either like the back, or else ashy — in one 



species, however, brown, and in another black ; and white 

 or whitish below, usuallj^more or less tinged with yellow. 

 riG. 58. Warbling Vireo. .pj^^ coloration is very constant, the sexes being indistin- 

 guishable, and the young differing little, if at all, from the adults. All are small 

 birds — about 5 or 6 inches long. As a group the student will probably have no 

 difHcultjr in recognizing them by the foregoing diagnosis, as the character of the 

 feet seems to be peculiar, among North American birds, and is at any rate 

 diagnostic when taken in connection with the character of the bill — all those 

 Oscines, as wrens, creepers, or titmice, that show much cohesion of the toes, 

 having an entirely ditTerent bill. The bill of Vireo may be described as resembling 

 that of a shi-ike in miniature — it is hooked and notched distinctly at the end, and 

 there is sometimes a trace of a tooth behind the notch, and of a nick in the under 

 mandible too. Some of the weaker-billed species might be carelessly mistaken for 

 warblers — but there is no excuse for this, nor for confounding them with any of 

 the little clamatorial flj'catchers. 



. The Vireos were long supposed to possess either nine or ten primaries. But that 

 the important character of number of primaries — one marking whole families as 

 we have seen — should here subside to specific value onlj^, seemed suspicious; and 

 the fact is, as announced by Baird (Review, pp. 160, 325) that all the species 

 really have ten, only that, in some instances, the first primarj' is rudimentary and 

 displaced, lying concealed outside the base of the second quill. 



The North American species are distributed over the temperate portions of this 



