The Fanniidae are a small, primitive group of Calyptratae, largely confined to the Holarctic and temperate Neotropical regions.
Adults are medium-sized to small species and are often mainly dark in body and leg color.
Larvae are characterized by their flattened bodies with striking lateral protuberances, and live as scavengers in various kinds of decaying organic matter. Afrotrop., Nearctic, Oriental, Palearctic Regs.