The Jenny Spinners in my neck of the woods emerge just before trico season starts and then starts to taper off towards the peak of the tricos.
They begin to hatch an hour or so after the last trico falls, so there is some time to get out of the water to pee and have another two cups of coffee before they start.
I have found them usually emerging from fast water very close to the edge, and Bruce picks up a lot swinging nymphs and wets there while I fumble around trying to look like I know what I'm doing while he makes fun of me.
The size 20 duns look huge compared to the tricos, and the fish smack dun and emerger patterns in this fast water.
I personally have never found rising fish during a spinnerfall, but hope spring eternal...
The spinners have what looks like a clear/transparent abdomen, and are quite a beautiful mayfly.
From a previous thread that I have saved:
According to Edmunds, the females will mate more than once and often proceed to shoreline foliage when finished with ovipositing as opposed to dying spent on the water. The males start the swarms first, often well before. They are often observed along the shoreline dipping from six to two feet and rising again. On occasion, many males for unknown reasons drop to the water at this time and become trapped in the meniscus. When the females finally arrive, they join them quickly at the top, copulate during the four foot fall, and just as quickly make short dives to either dip their abdomens into the water or land on the water to lay their eggs. Then it's up and back at it until they're finished. Edmunds reports that they will repeat this cycle as many as three times before they occasionally die spent on the water or more often head back to the bushes. This is good information for the angler to note.
I have tied some spent and sunken spinners with extended monofilament abdomens in the hopes of finding this activity, but sadly I haven't been so lucky.
I'm probably fumbling around again because when I start to see the spinner dance, the tiny olives start to come off and, well, you know about me and my attempts to break Marinaro's curse...