The ground beetles are generally insects of large size, with well chitinized teguments, often adorned with brilliant or metallic colors.
Ground beetles are primarily carnivorous and most species are nocturnal; starting after dusk, they leave their day-time burrows or hiding places to hunt for prey above ground. Favoured prey include small invertebrates such as slugs and snails, as well as other insects. Many carabid species are beneficial insects in agricultural settings, as they consume pest insect species.
Calosomes (genus Calosoma), another kind of ground beetles, are diurnal insects, of robust form, with more or less square elytra. Their habit of feeding on larvae of moths (they are known also as caterpillar hunters) makes them very useful and beneficial insects.
There are many different subfamilies in the family Carabidae which are not represented here. Here are three examples to show the amazing variety that exists in this large family of beetles:
From left to right: Amara (a genus with mainly phytophagous habits, which is rare for the family), Brachinus (Bombardier beetle, able to project by the anus a gas jet at very high temperature, with a noise of explosion, from where its common name was derived), and Zabrus (another phytophagous ground beetle, which can damage cereal crops).