With bright orange coloration behind the head and underneath the abdomen, this species of giant stonefly can grow up to 3 inches in length.They are weak, uncoordinated-looking flyers –looking like they are constantly in a controlled crash landing. They are the largest species of all mayflies, stoneflies or caddisflies hatching on any western river. Depending on the river, you can find them from mid May to mid July.
Photo by Karen Weaver on 6/11/20 in Missoula, MT