They may be the most numerous predatory insects in certain systems. Hundreds of species of carabids occur in the Midwest. The adults of most species are dark brown or black, shiny, and somewhat flattened, with slender legs for running. A few are an iridescent blue or green. They are commonly found under leaves or debris, in cracks in the soil, or running along the ground.
Some species also climb into trees, shrubs, and crop plants looking for prey.
Adult ground beetles run quickly when disturbed, but they rarely fly. Some species emit a strong smelling irritant when handled. Many are nocturnal and some are attracted to lights at night. In general, arable land contains more carabids than does land planted to permanent crops such as clover or alfalfa. Most species are more common on clay than on sandy soils.