Lightning bugs are not really flies, they are beetles. They range in color sometimes yellow, orange or brown. They have two sets of wings. The second pair are used to fly. The first pair is used for balance and is a protective covering when they are resting. The adult fireflies communicate by flashing their lights. They also use their lights to find a mate. Only the adult fireflies can light up. They have an organ called a lantern that lights up. The firefly larvae live on the ground under bark in swampy places. The larvae eat snails.