A. Roger, I'm going to give you a couple of pieces of information that I got from two stonefly taxonomists in response to your question.

Dr. Richard Bauman, BYU, told me that he was on a field trip with some students and they were observing a large hatch of Hesperoperla pacifica. As the insects crawled out of the water and began to emerge from their exuviae, the wings were held upright as they began to pump blood into them. When they were full, the insects seemed to 'stretch' the wings, and then folded them - the left one first and then the right one.

Dr. Ken Stewart, No. Texas Univ., sent me the following: "Aquatic insects that fold their wings over the back, such as Plecoptera, have defined fold lines. For the forewings, this is almost exclusively at the "anal fold line" between the cubital and anal longitudinal veins. For the hindwings, that are usually more complexly folded like a fan, there are several foldlines between longitudinal veins." Unfortunately, Ken didn't say anything about which side was folded first.