The Limacodidae or Eucleidae are a family of moths in the superfamily Zygaenoidea or the Cossoidea; the placement is in dispute. They are often called slug moths because their caterpillars bear a distinct resemblance to slugs. They are also called cup moths because of the shape of their cocoons.

Urticating hairs or urticating bristles are one of the primary defense mechanisms used by numerous plants, almost all New World tarantulas, and various lepidopteran caterpillars. Urtica is Latin for "nettle", and bristles that urticate are characteristic of this type of plant, and many other plants in several families. This term also refers to certain types of barbed bristles that cover the dorsal and posterior surface of a tarantula's or caterpillar's abdomen. Many tarantula species eject bristles from their abdomens, directing them toward potential attackers. These bristles can embed themselves in the other animal's skin or eyes, causing physical irritation, usually to great discomfort. The term "hairs" is technically a misnomer, as only mammals possess true hairs. The scientific term for plant hairs is trichomes.