Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Photos of insects and people from the 2022 BugGuide gathering in New Mexico, July 20-24

National Moth Week was July 23-31, 2022! See moth submissions.

Photos of insects and people from the Spring 2021 gathering in Louisiana, April 28-May 2

Photos of insects and people from the 2019 gathering in Louisiana, July 25-27

Photos of insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Previous events


Family Psephenidae - Water Penny Beetles

black and orange beetle - Ectopria nervosa - female Psephenidae - Psephenus falli Water pennies - Psephenus herricki Water Penny - Psephenus herricki Freshwater Crustacean? - Psephenus herricki Psephenus possibly herricki - Psephenus herricki Psephenus herricki Insect Larva? - Psephenus herricki
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)
No Taxon (Series Elateriformia)
Superfamily Byrrhoidea (Pill, Water and Toe-winged Beetles)
Family Psephenidae (Water Penny Beetles)
Explanation of Names
Psephenidae Lacordaire 1854
Water penny: larvae are flat, often circular
16 spp. in 6 genera in our area(1), ~300 spp. in 15 genera total(2)
3-7 mm(1)
Adults flattened, usually dark:

Larvae aquatic, distinctive, cling to rocks and found more often than adults:
worldwide, most diverse in E. Asia; Eubrianacinae (represented in our area by Eubrianax) are circumpacific, Psepheninae (represented in our area by Psephenus) are primarily a New World group, and Eubriinae (the rest of our genera) are globally distributed(1)
Larvae on the underside of rocks of submerged wood in fast-flowing water. Adults on rocks and vegetation along streams.
Adults only in summer(1)
Larvae graze on algae; some are detritivorous(1); adults are short-lived
Life Cycle
semivoltine; larvae overwinter, pupate under riparian substrates or in water(1)
Print References
Internet References
Family page (Hammond 2009)
Works Cited
1.American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea
Arnett, R.H., Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). 2002. CRC Press LLC, Boca Raton, FL.
2.Order Coleoptera Linnaeus, 1758. In: Zhang Z.-Q. (ed.) Animal biodiversity: An outline of higher-level classification...
Ślipiński S.A., Leschen R.A.B., Lawrence J.F. 2011. Zootaxa 3148: 203–208.
3.Water Beetles of South Carolina
Janet Ciegler. 2003. Clemson University.
4.Lawrence J.F., et al. (2000-2005) Elateriformia (Coleoptera): descriptions, illustrations, identification...