In New Zealand and Australia, glow-worms are the larvae (maggots) of a special kind of fly known as a fungus gnat. Fungus gnats look rather like mosquitoes, and most feed on mushrooms and other fungi. However, a small group of fungus gnats are carnivores, and the worm-like larvae of these species use their glowing lights to attract small flying insects into a snare of sticky threads. One species, Arachnocampa luminosa, is found throughout New Zealand, and others occur in Australia. 

Hundreds of Arachnocampa larvae may live side by side on a damp sheltered surface, such as the roof of a cave or an overhanging bank in the forest. Their lights resemble a star-filled night sky. Māori call them titiwai, which refers to lights reflected in water.