Helpful hints:
Fish mid-morning, after the cicadas have started buzzing, but before the fish get too full with them to care, or twice-shy from being hooked already.
To find a place to fish cicadas, listen for the loudest buzz in the trees. I fished several areas, from above Cherry Run on out to Coburn. Where the loudest buzz was, the fish were- either there, or just downstream.
If there's a wind, try to find the bank on the windward side. Makes it easier to cast those big flies.
A dead drift works best, although a little twitch can help. When these flies drag, they drag bad. I did a lot of paying out line to keep them dead drifting downstream, but I advise against doing too much of that. Beyond about 40 feet, my hookup success was low, and the flies make a wake like a speedboat when retrieved for a new cast. Uncool.
No need to target risers, although personally I saw quite a few last week, even in midday (cloudy days; mostly not rising to cicadas, but it became obvious that they were happy to see them.)
Fish searching the water, along the shaded bank. Where you think there should be a nice trout, there probably is.
I did much better in the pools than in the fast water. Even the long, slow pools, as long as there was a bit of current to drift the fly.
Use the best imitation you have- I think that when there was lack of interest in my imitation, it was because it was too small! I had a couple of cicadas land on me- honest, they're nearly the size of hummingbirds. (And up-close, their chirp is as loud as a wind-up alarm clock...staring at you the whole time...) Really, you don't want to have to throw a fly that big, but I think the best imitation would be 1 3/4"-2", tied along a 2x or 3x #2 or #4 hook. The best imitations should be like huge black sponge rubber beetles with a strip of burnt orange along the hook on the bottom, and ribbed with orange thread. Body tied fat, like 3/4" wide. Orange/yellow krystal flash for the wings, if you have it. Splay some to the sides, so it lays down in the water, like real spent cicada wings. Add some black rubber legs, for a bit of motion on the drift.
Wet imitations should work too, tied with chenille, wool, yarn, etc. But nothing beat watching a big trout pounce on one of these on top.
Use a shorter leader, and a stouter tippet. It sounds weird, but you're basically throwing a bass bug at them. And the fish that have keyed on cicadas all seem to be, um, sizable. I lost a lot of hookups, and I think it was mostly due to either having too much line paid out on a downstream drift, or to using too long and fine a tippet, which put too much coiled slack in my presentation, and too much stretch on the strike. I was using a standard 9' 4X leader at first. An 18" tippet of 2X or 3X is a better idea. I lost the largest trout I've ever hooked when he ran across a rock shoal and frayed my 4X tippet after several minutes of battle. (Actually, that one went for a #8 orange Stimulator, in the evening; there are some big stoneflies hatching out of Penn's right now, too.)
If all that advice makes me sound like Mr. Trout Expert, believe me, I'm not. I also fished the evening rise at Penn's several times- and every night I was there, there was one- and I got shut out every time. Whatever I was selling, they weren't buying. Just like always.
