The Nannochoristidae are a family of scorpionflies with many unusual traits. It is a tiny, relict family of about eight species, with members of the genus Nannochorista occurring in New Zealand, southeastern Australia, Tasmania, and Chile, so is probably of Gondwanan origin. The adults look like scorpionflies with more pointed, elongated wings. Most mecopteran larvae are eruciform, or shaped like caterpillars. Nannochoristid larvae, however, are elateriform, or shaped like wireworm or click beetle larvae. They are also the only entirely aquatic Mecoptera. Wing venation suggests a close relationship to dipterans. They are predatory, primarily on the larvae of aquatic Diptera.