a member of the family Lasiocampidae (Lepidoptera), particularly as a larva which lives gregariously in the early stages, generally in a large silken nest or matting that is woven on, and sometimes envelops, the host plant —note 1. some species of tent caterpillars are serious forest defoliators, e.g., the western tent caterpillar (Malacosoma californicum) —note 2. some tent caterpillars do not construct true tents, e.g., the forest tent caterpillar (M. disstria) —synonym tent maker —see webworm This definition last updated 09/25/2008