CHAR. Rictal bristles wanting; the loral feathers with bristly points;
the frontal feathers generally not reaching to nostrils. Nostrils
varied, exposed or not covered by feathers, and generally overhung by
a scale-like membrane. Bill usually without notch (except in some
Middle American genera). Wings much rounded, about equal to tail,
which is graduated. Primaries ten, the first generally about half the
second. Basal joint of middle toe usually united to half the basal
joint of inner, and the whole of that of the outer, or more. Lateral
toes about equal, or the outer a little the longer. Tarsi scutellate.
The impossibility of defining any large group of animals, so as to
separate it stringently and abruptly from all others, is well
understood among naturalists; and the _Troglodytidæ_ form no exception
to the rule. Some bear so close a resemblance to the Mocking Thrushes
as to have been combined with them; while others again exhibit a close
approximation to other subfamilies. The general affinities of the
family, however, appear to be to the _Turdidæ_, and one of the best
characters for separating the two families appears to exist in the
structure of the feet.
In the _Turdidæ_ the basal joint of the outer lateral toe is united to
the middle toe, sometimes only a part of it; and the inner toe is
cleft almost to its very base, so as to be opposable to the hind toe,
separate from the others. In the _Troglodytidæ_, on the contrary, the
inner toe is united by half its basal joint to the middle toe,
sometimes by the whole of this joint; and the second joint of the
outer toe enters wholly or partially into this union, instead of the
basal joint only. In addition to this character, the open, exposed
nostrils, the usually lengthened bill, the generally equal lateral
toes, the short rounded wings, the graduated tail, etc., furnish
points of distinction.
Genera.
A. Lateral toes very unequal.
_a._ Culmen depressed basally, the interval between the
nostrils wider than the much compressed anterior half of the
bill. Plate on the posterior half of the tarsus continuous.
Catherpes.
_b._ Culmen compressed basally, the interval between the
nostrils narrower than the rather depressed anterior half of
the bill. Plate on the posterior half of the tarsus broken into
smaller scales. Salpinctes.
B. Lateral toes equal.
_c._ Length about 8 inches. Campylorhynchus.
_d._ Length less than 6 inches.
Bill abruptly decurved or hooked at the tip. Outstretched
feet not reaching near to end of tail. Thryothorus.
Tail longer than the wing, the feathers black, variegated
terminally with whitish … Subgenus _Thryomanes_.
Tail shorter than the wing, the feathers rusty, not
variegated with whitish … Subgenus _Thryothorus_.
Bill only gently curved at the tip. Outstretched feet
reaching nearly to or beyond the end of the tail.
Back without streaks. No distinct superciliary stripe.
Troglodytes.
Bill curved, sub-conical. Tail as long as wing.…
Subgenus _Troglodytes_.
Bill straight, subulate. Tail much shorter than wing.…
Subgenus _Anorthura_.
Back streaked with black and white. Cistothorus.
Bill short, stout; its depth equal to one half its length
from the nostril; gonys straight or even convex, ascending.
Crown streaked; no distinct superciliary stripe.…
Subgenus _Cistothorus_.
Bill elongated, slender; its depth less than one third its
length from the nostril; gonys slightly concave, declining.
Crown not streaked; a conspicuous superciliary stripe.…
Subgenus _Telmatodytes_.