There are over 40000 species of Carabidae worldwide.
The are generally black or metallic and have ridged elytra (wing covers). All of them (except Paussinae) have a groove on the foreleg tibia ,which contains hair used to clean the antennae.
They have a pair of pygideal (distal body part) glands in the abdomen which are used as a defence mechanism releasing noxious or caustic chemicals. The most famous are Bombardier beetles
They eat other invertebrates and most are nocturnal hunters