Limonia triocellata. Photographed at Wilson Tract, Norfolk County, Ontario on 1 October 2019.
Sighting and photos (c) wiggly_.
Field Notes - I think the scientific name is Drosophila melanogaster :)
Leucophenga scutellata
Identified as Leucophenga scutellata on Bowerbird by Tony D.: "A great looking fly! I believe a male Leucophenga - from what I can see the features fall within that genus, and further there are three species with males with a transverse white abdominal band. Following Bock's (1979) revision on Leucophenga, I believe this one is a male L. scutellata. For the other two species - L. gibbosa has infuscated wings, especially intense along the leading edge, and L. albofasciata lacks the black basal marks on each side of the scutellum."
15-20 on the underside of a basidiomycete fungus