While shapes and colors may vary widely, they are usually shiny. Black is a common color, sometimes with a metallic sheen of another color on their wing covers. Most ground beetles feed at night and hide in the soil or under debris during the day. Adults measure to one inch long and have a cone-shaped head and wide curving beak. They can cause a painful bite to a human if captured.
Some species are know to squeak if caught.
Females lay single eggs in cracks, under rocks or in other sheltered spots in summer, and new adults emerge around the following June. There is only one generation per year. They have large heads with black and white markings and long wings that extend to the end of their abdomen. Bald faced hornets may also act as pollinators of some plants. If disturbed these hornets will sting humans.