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 Icterince (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^- 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, OT Lark-warhlers (I). Bill notched, scarcely bris- 

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



GeothlypincB, or Thicket-^arhlers (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 tailJ^ 



HelminthophilincB, or Worm-eating Warblers (IV, V, VT). 

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



MniotiltincB, 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 Parulse and Mniotiltae are widely different.) 



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

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

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

 blotched. PerissoglosscB are characterized by the tongue. 



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

 noticeably broader than high, also notched, usually hooJced, 

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



* TUo-w Mniotihidce. — W. B. *^ Characteristics italicized do not 



belsD!' to other Warblers. 



