THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

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

There are four North American genera of creeping water bugs. One, Ambrysus is found in the Northwest. If the front of the pronotum has a deep indentation that the head is nestled in, and you found it in the Northwest, then you've probably collected Ambrysus.

This creeping water bug both creeps and swims into warm basin and valley streams of Oregon and Idaho. Ambrysus usually lives in clear streams and ditches. Apparently, they're not afraid to use their piercing rostrum if they feel like their in danger, so be careful when handling them live!

The front of the pronotum is concave, and the head is nestled into the concave portion. The sides of the pronotum continue around the side of the body such that lobes obscure about half of the underside of the first segment of the thorax. Ambrysus is oval in shape and has strongly raptorial front legs that are sharply pointed. The underside of their abdomen is densely hairy and the ends of the wings don't have veins. The antennae are small and not clearly visible; the hind legs have claws; and the abdomen doesn't have long breathing tubes.