Hinder margin of sternum with a single shallow notch on each side; furcula anchylosed to keel of sternum; no manubrium sterni. Skull long and narrow. Second joint of third toe considerably longer than the basal joint. (Beddard, Ibis, 1888, p. 340.)
Only two genera are known—Strix, which is almost cosmopolitan, and Heliodilus, peculiar to Madagascar.