Members of Hemiptera are largely terrestrial, but there are some species that are aquatic in both the immature and the adult stages.
Most aquatic hemipterans are found in well-vegetated unmoving water or in slow-flowing habitats.
Ambrysus mormon (below) is an exception because it is found in well-oxygenated running waters with gravel or rocky bottoms.
Ambrysus mormon has been found in the Yampa, White, and San Juan River Basins in Colorado.
Illustration courtesy of B.C. Kondratieff, Colorado State University.