Female Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly DunView 2 PicturesI've tentatively called this fragile, highly damaged dun a Serratella species. I had much better pictures of the species but lost them. It's about size 22, but good-sized trout were rising to this hatch; I suspect it has to do with the solid profile shown by the dark, almost-black wings that have given this hatch the name "Darth Vaders" among some Wisconsin anglers.