Many individuals present.
Was found in a partially dry creek. Has six legs and two long antennae. Has an orange lining around its body. There were multiple in the creek area.
"This species has a distinctive pale (usually W-shaped) dorsal marking on tergite 6, and all but the very darkest specimens (usually males) also have those markings on tergites 5 and 9." --Lloyd Gonzales (https://bugguide.net/node/view/253437)
This mayfly was up high on the wall. Best pic I could get.