This picture-wing fly is an endangered endemic species found only on the island of Oahu. It is closely related to D. planitibia and its relatives (Kaneshiro et al. 1995), but is distinguished by its wing markings, narrow wing shape, and complexity of the male genitalia. D. substenoptera is predominantly yellow with two black stripes extending down the entire length of the top surface of the thorax. The legs are yellow and lack long hairs on the dorsal surfaces. Body length is 0.171 in (4.35 mm), and the wings are 0.2 to 0.21 in (5.0 to 5.3 mm) long (Kaneshiro and Kaneshiro 1995). Montgomery (1975) determined that Drosophila substenoptera larvae inhabit only the decomposing bark of Cheirodendron sp. trees (family Araliaceae) and Polyscias sp. trees (family Araliaceae) in localized patches of wet forest habitat.