Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
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Family Phengodidae - Glowworm Beetles

Phengodes sp. (larva) - Phengodes Phengode - Phengodes large beetle larva (40mm) - Phengodes Glowworm!!! - Phengodes Is this a beetle? - Phengodes plumosa Glowworm Beetle? - Distremocephalus - male unknown Phengodes - Phengodes Unidentified insect - Zarhipis integripennis
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
Superfamily Elateroidea (Click, Firefly and Soldier Beetles)
Family Phengodidae (Glowworm Beetles)
Other Common Names
Glow-worms, Railroad Worms
Synonyms and other taxonomic changes
the Asian Rhagophthalmidae (~30 spp.) formerly included here as subfamily are now treated as a separate familyl(1)
Explanation of Names
Phengodidae LeConte 1861
23 spp. in 6 genera of 2 tribes north of Mexico, ~250 spp. in ~30 genera total(2)
Adult males have variously shortened/narrowed soft elytra, branched antennae, and bulging eyes; adult females are larviform (often all but impossible to tell from fully-grown larvae) and, like the larvae, have bioluminescent organs(2)
Distinguishing adult females from larvae, per J.M. Cicero: "Adult females are much larger, having supernumerated beyond the male instar count and/or grown larger on nutritional bases; we don't know which of these factors is responsible for the larger size. Zarhipis and Phengodes larvae, at least, have strong opaque dorsal sclerites while in the female, those markings are bleached and weak. Lastly, females have a semi-circular slit on the penultimate ventrite that is associated with a copulatory gonopore. Larvae don't have either."
New World; in our area, mostly so. US, with 1 sp. (Phengodes plumosa) reaching ON and all Mastinocerini restricted to sw. US (CA-TX)(2)(3)
adult females and larvae feed on millipedes(2); adult males do not feed
mostly nocturnal; males come to lights(4)