Rhyacophila is known throughout North America, and are represented by 123 species in the Nearctic region (Morse 1993).

   Rhyacophila larvae are mostly green in color, and live in the swift riffles of cool clean streams. They are predominantly predators, that feed on other small animals. Adults seem to be territorial never straying far from the riffle where they emerged.

   Larvae are free living , and don't build cases, or shelters. Shortly before pupation they move to a position under the stone or the stream bottom where they spin a silk dome like puparium covered with small pebbles, and grains of sand.

   Egg laying is accomplished by either diving, or crawling down objects protruding from the river. Swarms are usually very thick with hundreds of females flying, and crawling up and down rocks, trees, bridge pylons, or anything else sticking out from the water. Rhyacophila females don't carry a noticeable egg sack, but carry their eggs concealed in their abdomen. After crawling or swimming to the bottom they deposit a chain of small bead like eggs along the rocks on the bottom of the stream.

   Key to Family - Tibiae spurs foreleg 3, middle 4, hind 4. Ocelli present, male and female maxillary palps both five segmented, segment two globular in shape, segment five ending in a small point.

   Key to Genus - Hind wings less than 20 mm in length.