Mnesarchaea paracosma is a species of primitive moths in the family Mnesarchaeidae. It is endemic to New Zealand and can be found in the Kaikōura, mid and south Canterbury, MacKenzie, Otago Lakes, Central Otago, Dunedin, Fiordland and Southland areas. M. paracosma lives in a wide variety of habitats including tussock grasslands, shrubland, and damp native beech or podocarp forests, at a range of altitudes from around sea-level up to 1200 m. Adults of this species are on the wing from October to February and are day flying, although they are attracted to light at night.