This dark brown, hairy caterpillar is easy to recognize because of the nine pairs of fleshy appendages protruding from its body. The hagmoth larva is another of the slug caterpillars which have urticarial hairs and can produce serious dermatitis (stinging rash) when handled. Hagmoths are usually found singly feeding on low branches of shrubs and deciduous trees (oaks, other hardwoods, etc.).