An animal that lives in or on another animal (the host), which it consumes and eventually kills. Hence parasitoids may be regarded as intermediate between a true parasite (see parasitism) and a predator. Many wasps and other hymenopterans, and also some flies, are parasitoids for part of their life cycle, laying their eggs commonly in or on the larvae of other insects. The hatched parasitoids then use the tissues of their host for food during development into free-living adults. Idiobiont parasitoids paralyse or kill the host at the time of egg-laying. However, more common are kainobiont parasitoids, which allow the host to remain alive for extended periods. In some cases the parasitoid can prolong the development of the host larva and prevent it metamorphosing. See also hyperparasite.