Last night, my wife and I went Kayaking on Lake Natomas. At around sunset I started spotting these large yellow mayfly duns on the water. Not a huge hatch, but one every 20 yards or so. I managed to catch one and put him on my foot while we paddled back to the launch ramp. The one in the picture was the larger of the 2 that were hatching. I caught another (not pictured) that was a bit smaller and not as yellow. I thought maybe they were the same species and the larger was the male, and the smaller darker was the female???

Can anyone help ID this Mayfly? Sorry for the bad picture!