CHAR. Bill much shorter than head, slender, broad, and depressed at
the base, distinctly notched and decurved at the tip. Culmen
sharp-ridged at base. Frontal feathers reaching to the nostrils, which
are oval, with membrane above, and overhung—not concealed—by a few
bristles or by a feather. Rictal bristles extending beyond nostrils.
Tarsi booted or scutellate. Basal joint of middle toe attached its
whole length externally, half-way internally. Primaries ten; spurious
primary about half the second, which is shorter than the seventh.
Lateral toes equal.
The birds of this family are readily distinguished from the _Paridæ_
by the slender bill, notched and decurved at tip; much bristled gape,
sharp-ridged culmen, exposed oval nostrils, less adherent toes, etc.
They are much smaller than the _Turdidæ_ and _Saxicolidæ_, with much
more slender, depressed bill, longer rictal bristles, etc. The short
outer primary, with the primaries ten in number, distinguish them from
the _Sylvicolidæ_.
The following synopsis will serve to characterize the American forms
of their respective subfamilies. The species are all among the most
diminutive in size with the exception of the Humming-Birds:—
A. Wings longer than the nearly even and emarginate tail.
Scutellæ of tarsus scarcely or not at all appreciable. General
color olivaceous above. No white on tail.
Nostrils naked. Scutellæ distinct on inner face of tarsus only.
Head plain. … _Sylviinæ._
Nostrils overhung by bristly feathers. Scutellæ of tarsus not
appreciable. Head with a colored central crest … _Regulinæ._
B. Wings about equal to the graduated tail. Tarsal scutellæ
distinct. Above bluish; tail with white spots or patches.
Nostrils uncovered. Head plain; either bluish or black above.…
_Polioptilinæ._