This species is found in California and Oregon but not in Washington as far as I can determine. It would be interesting if it were found in Washington. If anyone has seen it please let me know. The nymphs show up in late summer and early fall. The adults usually show in September and October. They're found in fast water or the slower edges of fast water. Size ranges from 10-22 mm for the nymphs in the photos and 22mm for the adult (excluding cerci and antennae).