This one has been difficult to identify. I can't spot any of the gill remnants characteristic of Perlidae, but the wing venation (Venation: The pattern in which the veins on the wings of an insect are arranged. It is usually one of the most useful identifying characteristics.) seems to point in that direction. I tried keying it out as Perlodidae but arrived at Isoperla, every western species of which has significantly smaller bodies than this one.
Edit: See forum comments for a likely correct identification.
Female Dicosmoecus gilvipes (October Caddis) Caddisfly AdultView 16 PicturesI've been hoping to add a really good October Caddis to the photo collection here for years, but so far I had struck out on finding them on the river. Tonight, this one flew into the kitchen during a pizza party at a house along the river, and was quickly pointed out -- one of the perks of hanging out with other aquatic biologists! Maybe next year I can finally get a salmonfly on taco night or something.