Phengodidae

The beetle family Phengodidae is known also as glowworm beetles, whose larvae are known as glowworms. The females and larvae have bioluminescent organs. They occur throughout the New World from extreme southern Canada to Chile. The recently recognized members of the Phengodidae, the Cydistinae, are found in Western Asia. The family Rhagophthalmidae, an Old World group, used to be included in the Phengodidae.

Phengodidae
A male Phengodes
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Suborder:	Polyphaga
Infraorder:	Elateriformia
Superfamily:	Elateroidea
Family:	Phengodidae LeConte, 1861
Subfamilies[1]
Cydistinae Paulus, 1972 Mastinocerinae LeConte, 1881 Phengodinae LeConte, 1861
Synonyms
Telegeusidae Leng, 1920

Larval and larviform female glowworms are predators, feeding on millipedes and other arthropods occurring in soil and litter. The winged males, which are often attracted to lights at night, are short-lived and probably do not feed. Females are much larger than the males and are completely larviform. Males may be luminescent, but females and larvae have a series of luminescent organs on trunk segments which emit yellow or green light, and sometimes an additional head organ which emits red light, as in railroad worms.

This family is distinct from the fireflies (family Lampyridae), which may also be called "glow-worms" in its larval stage. According to a few recent studies, Phengodidae might possibly include (or be sister taxon to) the long-lipped beetles,[2] which are primarily differentiated from phengodids by the unusual modifications of their mouthparts; long-lipped beetles were treated as a family Telegeusidae but are most recently treated as a subfamily within the family Omethidae.[3]

A luminescent larva or female