THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Water scorpions are large bugs with raptorial forelegs, a long thin body and an equally long pair of specialized breathing tubes at the tip of the abdomen. Adults may be as long as 45 mm, not including the breathing tubes, which can add another 20 mm to their length. Nepidae inhabit a variety of streams, ponds, and swamps, lurking in the vegetation in shallow areas. They lie in wait for prey below the surface of the water, hanging head-down in a position similar to a praying mantis, with the tips of the breathing tubes just above the water's surface to obtain oxygen.

The unique shape and voracious hunting abilities of water scorpions makes them well-suited as educational tools and classroom pets. The nepid pictured above was collected in a runoff detention pond. They readily exhibit their feeding behaviors on a variety of other macroinvertebrates.