Adult (sexes similar).—Above, except rump, dark steel-blue; loral feathers black with gray bases; a more or less triangular patch above and behind ear-coverts chestnut, streaked with black, continued forward over eye and slightly connected across occiput by fine lines of chestnut; feathers of neck and upper back largely white basally, this showing as white lines; under tail-coverts black; remainder of under parts including axillars and wing-lining white, or very pale fawn, with conspicuous blackish shaft-lines producing a very striking appearance; rump rusty chestnut with blackish shaft-lines; tail-coverts, secondaries, and secondary-coverts black, slightly glossed with blue; alula, primary-coverts, primaries, and rectrices black, slightly glossed with dark green. Bill black; legs and nails brown. Length, 190 to 195. A male from Cebu measures: Wing, 123; tail, 102; depth of fork, 55; bill from nostril, 6; tarsus, 14. A female from Cebu, wing, 120; tail, 93; depth of fork, 46; bill from nostril, 6; tarsus, 14.
Young.—General color pattern as in the adult, but head and back less strongly glossed with blue; chestnut on head and rump much lighter; wings and tail dark brown instead of black, and inner secondaries tipped with white; lower parts heavily washed with fawn, and shaft-stripes shorter, browner, and less sharply defined, very faint or altogether wanting on abdomen and under tail-coverts; axillars, wing-lining, and flanks strongly washed with fawn, shaft-lines faint or wanting.
If the Philippine representatives of the mosque swallow be included with H. striolata, as they must be at present, this species has a considerable range but it appears to be very local in occurrence. It may be found in numbers in one part of an island and be altogether absent a short distance away. It often appears in large flocks and may disappear within a few hours. I found it nesting in Bohol Island in May and in the Island of Batan during June. The nest is a bottle-shaped structure of mud, plastered to a wall in a cave or to a beam beneath a building. The eggs are pure white; three from Bohol measure: 22.6 by 14.7; 22.3 by 14.2; 22.8 by 14.7.
Family MUSCICAPIDÆ.
Edges of mandibles smooth with a small notch near the tip of the upper one; bill moderately broad and flat; nostrils protected by a number of long frontal bristles; frontal feathers more or less antrorse (soft and pile-like in some genera), but not entirely concealing the nostrils; rictal bristles long, numerous, and stiff; wings and tail long, the latter extremely long in some species; first primary, rarely minute, usually from one-half to two-thirds as long as wing; tarsus and feet slender and weak, the former rather short. This family contains a great number of closely related genera the species of which, in many cases, are not easily determined except from adult males.
Typically the bill is broad and flat, but in certain genera it is narrow and scarcely differs from the bill of some Turdine and Silvine birds. The frontal nasal bristles, long rictal bristles, and the weak legs and feet, are the most reliable family characters of this group. In the typical flycatchers the skin is very thin and tender which, taken in combination with their small necks and large heads, makes their preparation as specimens very trying.
Some of the most beautiful birds found in the Philippine Islands belong to this family, but several of the species are plainly colored. The males in a few genera possess greatly lengthened tail-feathers; in some others the head is crested.
Genera.
- a1. First primary very small and less than tarsus, equal to about one-fifth of second primary, the latter nearly as long as the third. Hemichelidon (p. [431])
- a2. First primary longer and equal to,
or greater than, tarsus; second primary less than three times the
first.
- b1. Second primary longer, equal to
nearly three times the first.
- c1. Sexes unlike in colors; bill neither very broad nor flat.
- c2. Sexes alike in colors; bill broad and flat. Alseonax (p. [435])
- b2. Second primary less than two and
one-half times, and usually less than twice, the first primary in
length.
- c1. Tail decidedly shorter than wing; total length usually less than 150 mm.; wing less than 80.
- c1. Tail equal to or longer than wing,
sometimes very much longer.
- d1. Without a distinct fleshy eye-wattle and without an elongated nuchal crest.
- d2. With a distinct fleshy eye-wattle; and with either a full or a long nuchal crest.
- b1. Second primary longer, equal to
nearly three times the first.