186 VIEEONIDiE. 



Lanivireo), and the latter also into two {Vireo and Vireonella). The differences by 

 which these sections are distinguished are given below in the headings to each group 

 of species. The system here elaborated was, with slight modification, adopted in the 

 ' History of North- American Birds ;' but there, though the names Vireosylvia, Lanivireo, 

 and Vireo are called subgeneric titles of Vireo, they stand at the head of each species 

 with full generic rank. Dr. Covies, in his various writings, and in his most recent one 

 the ' Birds of the Colorado Valley,' advocates the use of Vireo in its widest sense ; and 

 the arguments put forward in favour of this view seem to us to be most worthy of 

 consideration. One of the chief, if not the only point of distinction between Vireo and 

 Vireosylvia (the presence or apparent absence of a spurious first primary) breaks down 

 on close examination ; for this feather proves to be always present, though sometimes 

 in a very reduced form. Moreover, in the case of V.fiavifrons and V. solitarius (birds 

 whose general appearance is so much alike that they have almost always been placed 

 under the same generic head), the different state of development of the first primary 

 in each points to their separation. 



In Vireo the legs are slender, the claws weak, and the lateral toes unequal. The 

 shape of the wings varies ; in some of the more migratory species they are pointed, in 

 others more rounded. The bill is slender compared with such genera as Vireolanius 

 and Cyclorhis, and abruptly decurved at the end as compared with Hylophilus. The 

 first plumage of the young resembles that of the adult, and is destitute of spots either 

 above or below. This character applies to the whole family. Twenty species are now 

 known to occur within the limits of Mexico and Central America, of which nine are 

 immigrants from the north during the winter season, coming in autumn and leaving 

 again in spring. Of these, only two pass beyond our limits into the northern parts of 

 South America. Besides these migratory birds, there are eleven more or less sedentary 

 species, whereof one {V. hypochryseus) is peculiar to Western Mexico and the Tres 

 Marias Islands, one ( V. ochraceus) is shared by Mexico and Guatemala, one ( V. pallens) 

 by Nicaragua and Costa Eica, and another (F. carmioli) by Costa Eica and Panama. 

 V. huttoni, a northern species, is said to be resident in Mexico ; and V. amauronotus is 

 also probably resident there. 



In their summer quarters the members of this genus are during the breeding-season 

 cheerful songsters ; but in the winter they only utter call-notes. 



A. Alee productw, acutce, cauda longiores ; remex primus minutus, aliquando 



ohsoletus. (Vireosylvia.) 

 a. Corpus attenuatum et elongatum ; rostrum debile, angustum, rectum ; pedes debiles. 



a'. Bemex spurius ohsoletus. 

 a". Pileus cinereus utringue fusco marginatus. 

 1. Vireo calidris. 



Motacilla calidris, Linn. Syst. Nat. i. p. 329 '. 



