My mantis eggs still haven't hatched!

I'm wondering if I got a bad batch of eggs or something. If they aren't hatched by the end of May, I'm going to assume they won't hatch. Maybe they dried out? I might have to start over with one of the other ootheca.

My patient and tolerant boyfriend has a Venus flytrap that he's feeding grain moths to. Grain moths are these ultra-annoying little moths that, well, inhabit grain and nuts and seeds. Any bag of seedy/grainy thing will soon get infested with the little white grain moth larvae, and then the moths grow up and commit suicide in any open container of liquid (all too often my drink). I have given some thought to releasing the mantises, provided they hatch, and letting them hunt down the moths--but maybe the Venus flytrap will take care of it instead.