Glowworm
Glowworm or glow-worm is the common name for various groups of insect larvae and adult larviform females that glow through bioluminescence. They include the European common glow-worm and other members of the Lampyridae, but bioluminescence also occurs in the families Elateridae, Phengodidae, and Rhagophthalmidae among beetles; as well as members of the genera Arachnocampa, Keroplatus, and Orfelia among keroplatid fungus gnats. Beetles. Four families of beetles are bioluminescent. The wingless larviform females and larvae of these bioluminescent species are usually known as "glowworms". Winged males may or may not also exhibit bioluminescence. Their light may be emitted  as flashes or as a constant glow, and usually range in color from green, yellow, to orange. The families are closely related, and are all members of the beetle superfamily, Elateroidea. Phylogenetic analyses have indicated that bioluminescence may have a single evolutionary origin among the families Lampyridae, Phengodidae, and Rhagophthalmidae; but is likely to have arisen independently among Elateridae. Fungus gnats. Three genera of fungus gnats are bioluminescent, and known as "glowworms" in their larval stage. They produce a blue-green light. The larvae spin sticky webs to catch food. They are found in caves, overhangs, rock cavities, and other  sheltered, wet areas. They are usually classified under the family Keroplatidae, but this is not universally accepted and some authors place them under Mycetophilidae instead. Despite the similarities in function and appearance, the bioluminescent systems of the three genera are not homologous and are believed to have evolved separately.