A group of butterflies is officially called a kaleidoscope, although they are sometimes referred to as a swarm. Groups of caterpillars are called an army.
Caterpillars can turn into butterflies or moths. "Caterpillar" is the name for the larval stage of the life cycle of insects in the order Lepidoptera, which includes all butterflies and moths.
Most adult moths eat nectar or simply do not feed, and moth larvae feed on many types of foliage and clothing fibers. Adult male moths of the Calyptra genus are capable of feeding on blood.