Fireflies are also called lightningbugs. However, they are neither flies nor bugs. They are actually beetles. There are 124 species in the U.S. and Canada. Most are found in the Southeast and the Deep South. Size varies with the species and ranges from to inch in length. Fireflies are rather soft bodied and their body is elongated and somewhat flattened. Fireflies may be brownish, black or olive in color. Many species have distinctive red or yellow markings. Adults are most active in the evenings, just after dark. Fireflies are most commonly found in the spring and early summer. Adults may be found on vegetation during the day. The females of some species are wingless.

Firefly larvae are flattened and spindle-shaped. They may be found under bark or in ground litter where they feed on snails, insects and other small arthropods. The larvae of many species glow in the dark and are called glowworms.

Most species complete a life cycle in two years.

The most noted characteristic of these insects is their ability to produce flashes of light. The light is produced from a light-producing organ located on the ventral side of the terminal segments of their body. This flashing may be witnessed in early evening. Often, hundreds of these insects, flashing on and off will light up the night. The light is produced when the compound luciferin reacts with the enzyme luciferace, and is oxidized. Practically all of the energy produced by this reaction is in the form of light.

The frequency of flashing, the duration of the flashes and the time interval between flashes vary with each species. Fireflies flash their light to find a mate. Males fly around flashing their specific signal. Females detect a male of their own species and answer back. Thus, the males and females are able to find one another. Predaceous females of some species will mimic the flashing of another species. This attracts the males of the other species, which are quickly devoured by the predaceous female.