I was talking to the retired KDWP Fisheries Bioogist, Ken, (also a fly fisher) at our board meeting last Thursday. I asked him about a few other mays I've seen while out fishing in KS. He said there are hundreds of species in KS, but I would have to agree with Jeffro and BG222. I'll bet there were both sexes out. I've seen bright yellows hexes and darker ones out at the same time and assumed they were M n F. I have snapped some pics of different mays this year, hoping for some answers.