These photos supplement page 140 of the Guide to Aquatic Invertebrates of the Upper Midwest. Information on the biology of Pyralidae can be found on page 140. Aquatic moths have 3 pairs of thoracic legs. Also, they have crochets on the ventral side of their abdomen. These crochets are what distinguish them from aquatic beetle larvae, which can look similar. Click to compare with Chrysomelidae beetles.