Rhagophthalmidae

The Rhagophthalmidae are a family of beetles within the larger Elateroidea group that include click-beetles. Members of this beetle family have bioluminescent organs on the larvae and are closely related to the Phengodidae (glowworm beetles) and Lampyridae (fireflies), and were often included in one of these families as a subfamily—Rhagophthalminae. Towards the end of the 20th century, they were increasingly seen as a distinct family. But they might be the only reasonably close living relatives of the mysterious fireflies of genus Pterotus, and could eventually end up in a Lampyridae subfamily with these. They were mainly included in the Phengodidae for having similar adaptation for displaying glowing lights. However, this seems to be due to convergent evolution. If they indeed belong in the Lampyridae, they are related to a group of families that have either a distinct type of flashing lights (Luciolinae) or rely exclusively or nearly so on pheromones for communication (the others).

Whatever their relationships may be, Rhagophthalmidae are distributed in the Old World, and little is known of their biology. Females are usually wingless and look like larvae, but have an adult beetle's eyes, antennae and legs; in the genus Diplocladon, they resemble larvae even more with their small light organs on all trunk segments. Larvae and females live in soil and litter and are predaceous; males may be attracted to lights at night.