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Phylum Arthropoda
Class Insecta
Order Hemiptera
Suborder Heteroptera
Family Nepidae
Common Name Water-scorpion
Distinguishing Characteristics
  • Somewhat resemble a scorpion
  • Raptorial forelegs
  • Presence of two long slender breathing tubes on abdominal apex
Additional Pictures
     There are 13 species in 3 genera found in the United States and Canada. Larvae and adults range from 18-46 mm in length with a 16-44 mm breathing tube. Slow moving streams, ponds, and similar bodies of waters are common habitats to find Nepidae. Categorized as predators, Nepidae primarily feed on invertebrates and occasionally on small fish or tadpoles.

     Nepidae have nonretractable breathing tubes and middle and hind legs adapted for walking rather than swimming.

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Additional Links



Merritt, R W., K W. Cummins, and M B. Berg. An Introduction to the Aquatic Insects of North America. Dubuque, Iowa: Kendall/Hunt Company, 2008.

"Family Nepiade – Water scorpions." Bugguide.Net. 6 April 2004. Iowa State University Entomology. 16 May 2008 <http://bugguide.net/node/view/109>.