Different types of Magicicada periodical cicada holes found in Princeton, NJ. Brood X, 2021. Generally speaking, their holes are about the size of a dime. You won’t see a spray or kickback of soil around the hole like you would when an animal is digging into the soil rather than coming out of it (cicadas are coming out).
Typical dime-sized cicada holes
A hole with a corresponding mini cicada-chimney
A golf ball sized chimney over a hole
A hole borrowed into a hay bale laying on the ground
A hole in moss
Holes in the underside of a rotten log, with a nymph!
Cicadas will burrow up from the soil of the ground and keep going into the rotting wood of a rotten log! I had to roll the log over to see it.
These are some small cicada chimneys created by Magicicada during Brood II in 2013 in Metuchen. Magicicadas occasionally create chimneys above the holes they emerge from — more often when the soil is wet or ground is shadowed (under a deck, in a lawn mower shed). These were shaded by a large pine.