I imagine a smaller cicada pattern adjusted for color or even a big *** EWC would suffice, but I have yet to see any dropping in creeks or ponds.
They stay up in the trees, seem to go where they want because they can hop & fly well and don't die off in droves like cicadas.
The good news is recent reports of sightings in Berks County are WAY down this year.
If you want a test laboratory, go to French Creek State Park in August. They were all over the place last year but again, I didn't see any in either of the lakes and when I threw a few into Scott's Run, they were shunned by the bluegills.