phengo-, pheng- +

The females and larvae have bioluminescent organs. They occur throughout the New World from extreme southern Canada to Chile. The family Rhagophthalmidae, an Old World group, used to be included in the Phengodidae.

Larval and larviform female glowworms are predators, feeding on millipedes and other arthropods that exist in soil and litter. The winged males, which are often attracted to lights at night, live for a short span 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 exhibits red light, as in "railroad worms".

Human manifestations of this fear involve secluding themselves in curtained rooms where sunlight can not enter and only allowing illumination by artificial light. Usually the individual can go out at night and move around in greater comfort than during daylight.