It looks simular to traps my neighor used to trap Japanese beetles. The only difference is his also had a metal cap simular to a cap you would see on a vent pipe. The beetles would fly under the cap, go down through the hole and like a minnow trap, have a hard time finding the hole to get back out. The screen looks to fine for a minnow trap, it would catch to much silt and debris, the hole also looks to small for a minnow trap.