Austrosimulium ungulatum, the West Coast black fly, is a species of small fly in the family Simuliidae (the black flies). It is endemic to New Zealand, where it occurs in the South Island and Stewart Island. Simuliids in New Zealand are known locally as "sandflies" and, in Māori, as "namu". The species was first formally described in 1925 by Belgian entomologist André Léon Tonnoir. The females take blood meals to obtain nutrients for egg production. They are known to feed on the blood of Fiordland penguins, and spread the blood parasite Leucocytozoon tawaki to them. It is one of three New Zealand Austrosimulium species that commonly bite humans, and is notorious for doing so prolifically. In their larval stage, they live in small, well-shaded streams that have a cool temperature, where they are preyed on by fish such as the torrentfish.

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