I understand that certain populations of parsonii love cicadas, and that they compose a large portion of their diet. If there's a reason parsonii are as big as they are, and have such massive jaws, cicadas could be that reason.
I hear melleri like them too. I'm just a bit apprehensive of feeding an animal that's spent many many years in the ground, giving it a longer time to be exposed to parasites and pesticides.
I've heard horror stories abotu katydids. A friend of mine used them to get freshly imported parsonii to start eating. Thing was, they seemed to be loaded with parasites in his area.