Drosophila tarphytrichia is an endangered species of fly from Hawaii, in the species rich lineage of Hawaiian Drosophilidae. It is only found on the island of Oahu. While originally collected near Manoa Falls in 1949, this fly is thought to have been extirpated from the Koʻolau Range and now only found in the Waiʻanae Range. This species is a member of the lanaiensis subgroup in the picture-wing clade.