Modular Wasptrap / Flytrap. 

Simply cut holes into the sides of a bucket or plastic canister and clip in the tunnel fitting for your hole saw size. 

To trap Wasps, add fruit juice to the bucket, to attract flies, add an egg and water, but beware, this stinks a lot. But its very effective.

You can print it with supports under the clips if you want a clean fit, but it also works without.

Onshape Model fully modular, you can change it for any size holesaw or bucket thickness. 

https://cad.onshape.com/documents/502b87749c67741515f87ae8/w/545f75ad007ee58bcec6fc9d/e/558032919b69f01b5162e3d3