WARBLERS. 79 



a distance and high in the air, resuming their work, if it may 

 be so called, when they alight. They retire in summer to 

 breed in Labrador and other cold countries, where they are 

 said to sing. 



d. When with us their only note is a feeble one, a simple 

 chirp, which is often repeated. 



§ 9. The SYLVICOLID^,* or American Warblers, form 

 a group, which may perhaps be best defined negatively. By the 

 omission, however, of the Icterinm (or Chats), who probably 

 should be ranked as a family intermediate between the War- 

 blers and Tanagers, their characteristics may be considered the 

 following. Length, 4-6 1- inches ; bill twice as long as high ; 

 commissure entirely straight or slightly curved, unless inter- 

 rupted by a terminal notch ; nostrils exposed ; tarsus scutel- 

 late ; " hind toe shorter than the middle " ; primaries nine (fig. 

 4). It is doubtful how many subfamilies there should be, 

 but the following well-defined groups exist. 



Seiurince, or Lark-ivarhlers (I). Bill notched, scarcely bris- 

 tled. Birds streaked beneath. Tail not marked or forked. 



Geothlypince, or Thicket-warhlers (II, III). Bill notched, 

 scarcely bristled. Birds wholly unstreaked. Tail not marked 

 or forked. In Geothlypis, the wings are approximately equal 

 in length to the tail.^ 



HelminthojMlince, or Worm-eating Warblers (IV, V, VI). 

 Bill acute, unbristled and unnotched^ (pi. 1, fig. 7). 



Mniotiltince, or Creeping Warblers (VII, VIII). Bill 

 scarcely bristled, and never (very) distinctly notched ; hind 

 toe much longer than its claw. (Except in structure, how- 

 ever, the Parulae and Mniotiltae are widely different.) 



Sylvicolince, or Wood-warblers (IX, X). Bill notched, and 

 with short bristles (pi. 1, fig. 8). Tail not unmarked, unless 

 in (Estiva, where it is slightly forked. In other cases white- 

 blotched. JPerissoglossce are characterized by the tongue. 



Setophagince, or Fly-catching Warblers (XI, XII). Bill 

 noticeably broader than high, also notched, usually hooTced, 

 and always with long bristles^ (pi. 1, fig. 9). 



* Now Mniotiltidce. — W. B. 4^ Characteristics italicized do not 



belong^ to other Warblers. 



