Calosoma is a genus of large ground beetles that occur primarily throughout the Northern Hemisphere, and are referred to as caterpillar hunters or searchers. Many of the 167 species are largely or entirely black, but some have bright metallic coloration. They produce a foul-smelling spray from glands near the tip of the abdomen. They are recognizable due to their large thorax, which is almost the size of their abdomen and much wider than their head.