“Young.—Young individuals are paler above and below, the dark markings less developed, and pervaded with a sandy rufous tinge; the young male shows already the white spots of the adult male, but they are shaded with buff and that on the second quill is a little interrupted.” (Hartert.)

Worcester and Bourns took a male of this species in Palawan in December, 1891. It was 260 in length; wing, 212; tail, 128; culmen, 12; tarsus, 14; middle toe with claw, 22. The second Philippine specimen was shot by my assistant in Calayan Island, the last day of 1903. This specimen measures: Length, 260; wing, 210; tail, 127; tarsus, 15; middle toe with claw, 21. Bill and legs brown; nails black; the stomach contained several beetles and a large mantis.

The species appears to be a migrant from Asia and although not uncommon in Calayan we secured but one specimen. The male is distinguished from the other Philippine species by having a subterminal white tail-band; the female is distinguished from the females of C. manillensis and C. macrurus by the lack of a large white tail-spot and from C. griseatus by the much darker plumage and larger size.

Suborder MICROPODII.

Bill small and weak, the gape deeply cleft; rictal bristles not obvious; legs and toes small and weak; middle toe-nail not pectinate; tarsus very short; tail short to moderately long, either square or forked, and not reaching the tips of the folded wings. Diurnal in habits; eggs pure white, two in number; nest composed of sticks and moss, or else wholly or in part of a salivary secretion.

Families.
Family HEMIPROCNIIDÆ.

Swift-like; wings long and pointed, tail deeply forked; feet stout; tarsus shorter than middle toe without claw; colors largely blue and brown with a slight metallic gloss; plumage of the sexes dissimilar; at once distinguished from any nearly related family by the elongated white feathers above and below eye. Habits more flycatcher-like than swift-like.

Genus HEMIPROCNE Nitzsch, 1829.[37]