VIREONID^. 



323 



scutellatc anteriorly. The young are never spotted, nor streaked as 

 in the Thrushes ; nor indeed do the adults exhibit such markings. 



In the adhesion of the toes at their bases there is some resemblance 

 to the Troglodytidse, but their structure is different. In the latter 

 family the joints are lengthened, the basal of the middle, about as 

 long as the 1st and 2d of the outer, and equal to or a little longer 

 than the basal inner. In Vireonidee the basal joints are abbreviated ; 

 the basal of the middle equal to about one and a half joints of the 

 outer, and not quite as long as the basal inner. This difference is, 

 perhaps, related to the more or less terrestrial habitat of the one, and 

 the strictly arboreal of the other. In Vireonidse, too, there is a 

 greater tendency to having three rows of scales on the upper part 

 of the palm, on the three toes respectively, instead of having the 

 outer two rows united more into a single series. 



The young of Vireonidse, before the first full moult — at least 

 those of Vireo, Vireosylvia, and Hylophilus — are not spotted as in 

 Turdidse and Myiadestes, but closely resemble the adult. 



The Vireonidse are peculiar to the jS'ew World, and are generally 

 distributed. Laletes and some species of Vireo and Vireosylvia 

 are peculiar to the islands ; Hylophilus extends to Trinidad and 

 Tobago ; the other genera are confined to the Continent. 



The following synopsis of the genera may serve to facilitate their 

 determination — the primary division being based on the character 

 of the toes : — 



Legs slender ; claws weak ; lateral toes unequal ; the inner claw 

 reaching about to the base of middle one, the outer nearly 

 half way towards its tip. 



Bill slender ; culmen straight, at least for basal half; quite 

 abruptly and considerably decurved at the end. 

 Wings pointed, considerably longer than the nearly 

 even tail ; spurious quill either wanting or very 

 short, not one-third the second . • . Vireosylvia. 

 Wings rounded, rather longer than the more or 

 less rounded tail ; spurious quill lengthened, 

 one-third or more the second ; second gener- 

 ally, and third almost always longer than 

 secondaries ; third or fourth quill usually 

 longest. Bill rather compressed . . . Vireo. 

 Wings much graduated, shorter than the consider- 

 ably rounded tail ; the sixth quill longest ; 

 second quill much shorter than secondaries ; 

 third scarcely longer. Bill short, more de- 

 pressed, and broader between angles of mouth 

 than in Vireo Neochloe. 



