Glowworms, a family of beetles known as the Lampyrineoe. Their popular name is derived from the fact that the female, a wingless, grub-like insect which lives on grass, emits a bright green light from a spot on the abdomen. They are common and widely distributed all through England and Central Europe, and their luminous spot meekes them very conspicuous. The male of the common English species is less generally known; it is a light-brown insect about half an inch in length, and is only very slightly luminous. The use of the light to the insect has been much discussed, but it is probably a secondary sexual character, serving to guide the male to the female; it may also serve in part as a protection against birds. The origin of the light in the glowworms. fireflies, click beetles, etc., is discussed under Phosphorescence (q.v.).