1. 



Typical group. 

 2. 

 Sub-typical group 



204 NORTHERN ZOOLOGY. 



Here again we have the aberrant groups united by such birds as Setophaga 

 rubra, Sw. * where the form of the bill is completely that of an Accentor, joined 

 to the remarkable and otherwise inexplicable character of a strongly-bristled 

 rictus. The analogies of the whole group are highly interesting, both in reference 

 to the external anatomy, and to the habits and economy of the living birds. 



Contracting the sphere of our inquiries, we shall select, for further analysis, 

 the genus 



SYLVICOLA, Sw., 

 as a group which more particularly regards the Warblers of North America. 

 Here again we find three divisions, typically distinguished by the following pecu- 

 liarities : — 



Sub-genera. 



J- Bill entire, acute, pointed, sub-conic . Vermivora, Sw. 



\ Bill obsoletely notched, slightly bent . Sylvicola, Sw. 



3 - I Hind toe raucb stronger, and more length- I ' 



., f i i ii • i Zosterops, H. and V. 



Aberrant qroup. ened ; bill various . . . I f 



y l J I Mnwtdta, Vieil. 



The paucity of species in the two extreme aberrant types, viz., Dumecola and 

 Mniotilta, prevents us, at present, from knowing in what way they may be united. 

 We shall therefore state the affinities and analogies of the whole group more in 

 detail. The typical distinctions of the entire genus 



SYLVICOLA 

 consists in the bill being lengthened-conic, either entire, or slightly notched re- 

 motely from the tip of the upper mandible, which is scarcely deflexed ; wings 

 pointed, the first quill nearly as long as the second. 



The circular union of these groups must be explained more fully in another 

 place ; for the present it is sufficient to state, that Wilson, more than twenty years 

 ago, clearly pointed out in what manner the worm-eating Warblers (Vermivorw) 

 differed from the true Syhicolce, with which, nevertheless, all subsequent writers 

 have continued to blend them f . As yet we have actually seen but one species of 

 Dumecola, although we strongly suspect the Musicapa diops, PL Col. 144, f. 1, is 



* Synop. of Mexican Birds, No. 19. 



■J- These birds have recently, indeed, been erroneously placed with the sub-genus Dacnis, belonging to the Cinny- 

 ridcB. This resemblance between the two groups is certainly strong, but it is only analogical. — Sw. 



