THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

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

The Philopotamidae build finger-like nets on the underside of rocks. They use the nets as shelter and to efficiently filter organic particles from the water. They are common and sometimes abundant in stream samples, but are not commonly encountered in wetlands. Live specimens are yellow and wiggle actively through the water column; preserved specimens turn white.

Philopotamidae have the well developed anal prolegs typical of free-living caddisfly families. Only the first thoracic segment is covered by a plate. Their most distinctive character is a pale, fleshy,T-shaped labrum at the front of their head above their mandibles. They use this labrum to collect food from the inside of their net.

Size: medium to large
Identifying feature(s): yellowish body; wiggle actively through the water column; pale T-shaped labrum
Habitat: under or on rocks in riffles in streams
Tolerance to pollutants: sensitive to tolerant.

Images on this page are from www.nwnature.net, and were used with permission from Michael Clapp.