Mantis egg cases
I went looking for egg cases today (May 9) and believe to have found some that have not hatched yet. Is there a way to tell if a case has hatched yet?
Wayne County Michigan praying mantis
The babies eat their way out of the case, so there should be signs of this. Perhaps the photos here will give you some clues: https://www.landrethseeds.com/newsletters/Volume%207/Issue%204-Praying%20Mantis/Garlic.html