These photos supplement pages 119-135 of the Guide to Aquatic Invertebrates of the Upper Midwest. Information on the biology of Philopotamidae can be found on page 132. Philopotamidae have a sclerotized pronotom, but a membranous meso and meta notum. The dorsum of segment 9 is membranous as well. The main identifying character is the long T-shaped membranous labrum. Philopotamidae do not build cases.