Predaceous ground beetles are medium to large soil-dwelling beetles, often about 1/3 to 2/3 inches (8–16 mm) long. Over 2,500 species are known in North America. Their shape and color varies greatly. Adults are often black or dark reddish, although some species are brilliantly colored or iridescent. Most species have a prominent thorax that is narrower than their abdomen. Their long antennae have 11 segments and are not clubbed at the end. They have long legs, are fast runners, and rarely fly. Carabids resemble plant-feeding darkling beetles. Unlike darkling beetles, carabids have enlarged basal segments (trochanters) on their hind legs. Darkling beetles' antennae are attached beneath a distinct ridge on each side of their head; carabids lack this ridge.
Carabid adults and larvae feed on soil dwelling insect larvae and pupae, other invertebrates such as snails and slugs, and sometimes on seeds and organic litter. Eggs are laid in moist soil. Larvae dwell in litter or in soil. Larvae are elongate and their heads are relatively large with distinct mandibles. Most species complete their life cycle from egg to adult in one year. Metamorphosis is complete.
