Our campus museums consortium is assembling a series of exhibits on "real vs. fake objects/histories in a museum setting" including forgeries, fabrications, and frauds (but also replicas and reinterpretations).
I am aware of some entomological examples, like this fossil fly:
And maybe Richard Meinertzhagen's frauds touched on entomology, specifically lice?
Are you aware of any others that would be worth highlighting?
Thankful for any exciting tales,
Frost Entomological Museum