• See Nepa.
any of the approximately 150 species of aquatic invertebrates of the family Nepidae (order Hemiptera). The water scorpion resembles a land scorpion ... [1 related articles]
Wa'ter scor'pi·on (Zoology) See Nepa . 
The water-scorpion is an insect of the order Hemiptera, which lives in fresh- water ponds and preys upon other insects.
[n] - long-legged aquatic insect having the front legs fitted for seizing and holding prey and the abdomen extended by a long breathing tube
noun long-legged aquatic insect having the front legs fitted for seizing and holding prey and the abdomen extended by a long breathing tube