Found buzzing around me indoors.
See https://cjai.biologicalsurvey.ca/mmg_31/mmg_31_key.pdf#page=139 for diagnosis of the species.
The end of the abdomen indicates a female.
Acletoxenus formosus-Arthropoda-Hexapoda-Insecta-Pterygota-Diptera_Brachycera-Cyclorrhapha-Schizophora-Acalyptratae-Ephydroidea-Drosophilidae_Steganinae-Acletoxenus