_Petrochelidon_, CAB. Mus. Hein. 1850, 1851, 47. (Type, _Hirundo
melanogaster_, SWAINS. = _P. swainsoni_, SCL.)
[Line drawing: _Petrochelidon lunifrons._
18322]
GEN. CHAR. Bill stout and deep, somewhat as in _Progne_. Nostrils
entirely superior, open, without overhanging membrane on the inner (or
upper) side, but somewhat overhung by short bristles, seen also along
base of inner mandible and in chin. Legs stout; the tarsi short, not
exceeding the middle toe exclusive of its claw; feathered all round
for basal third or fourth, though no feathers are inserted on the
posterior face. Tail falling short of the closed wings, nearly square
or slightly emarginate; the lateral feathers broad to near the ends,
and not attenuated.
Of this genus as restricted we have but one species in North America,
although several others occur in the West Indies and the southern
parts of the continent. All have the back steel-blue, with concealed
streaks of white; the rump, crissum, and a narrow nuchal band, and
usually the forehead, chestnut.
Petrochelidon lunifrons, BAIRD.