The egg, larva and male all emit a luminescence, however it is the glow from the last three tail segments of the female glow worm that is usually seen. The female is a dark brown wingless beetle, measuring up to 25mm. The male looks like a beetle with wings, with a fluttery, almost moth-like flight and large eyes that are used to spot females. The larva, which hatches from an egg, has six legs at the head end, is black, and made up of 13 body segments, each having two yellow spots on the hind corners.