Drosophila montgomeryi was described by Hardy and Kaneshiro (1971) from specimens collected in the Waianae Mountains of Oahu in 1970. Morphologically, this species appears to be most closely related to D. pisonia from the island of Hawaii. It can be distinguished by the narrow, pale brown stripe on each side of the top of the thorax, the long hairs on the front legs, and the second antennal segment, which is yellow, tinged with brown on the top. Montgomery (1975) reported that the larvae of this species feed within the decaying bark of Urera kaalae, a federally-endangered plant (USFWS 1991, 1995) that grows on slopes and in gulches of diverse mesic forest (Kaneshiro and Kaneshiro 1995). The picture wing group is divided into four major subgroups based on maps of chromosomal inversions. Drosophila montgomeryi is in the glabriapex subgroup (Edwards et al., 2007).