Lampyris noctiluca, the common glow-worm, is a firefly species of the genus Lampyris. These are beetles, belonging to the genus of the Elateriformia.

Fireflies, such as Lampyris noctiluca are in several ways exceptional.

• Lampyris noctiluca presents a conspicuous sexual dimorphism. The males are winged, with brown elytra, a clearer pronotum and a large brown spot in the middle, while females are larviforme, wings are missing and they are often twice the size of the males.
• These beetles use their bioluminescence to attract mates. The adult females are mostly famed for their glow, although all stages of their life cycle are capable of glowing. Females emit a yellowish-green light from the translucent underside of their last three abdominal segments to attract the smaller males, which are winged. They will glow for 2 hours and then retreat back into their hiding place until the next night, or stop glowing as soon as they find a mate. The females can survive up to 10 consecutive nights doing this. The insect can regulate its light production by controlling the oxygen supply to the light emitting membranes containing luciferin. Virtually all of the energy produced is light; only 2% is heat.

The individual on this image is a female.