https://www.minnesotaseasons.com/Insects/spiny_crawler_mayflies_Ephemerellidae.html
Spiny Crawler Mayflies (Family Ephemerellidae) — Minnesota Seasons
Spiny Crawler Mayflies are a diverse family of aquatic insects whose stout, often spiny nymphs feature plate-like abdominal gills and three long tail filaments.
spinycrawlermayfliesfamilyephemerellidae