Image acquired with permission from the London Natural History Museum. Specimen collected by Wallace. Specimen locality: SingaporeLabel transcription: LECTO- / TYPE // ♂︎/ Type // SING. // Syrphus / duplex, Wlk. ♂︎// duplex n.s. // LECTOTYPE / Syrphus / duplex Walker / Design. Thompson 1972 // NHMUK010863951