Me: I want to know how to tell if an ootheca has hatched and I can't find anything on Google to tell me, amazingly enough. I thought maybe you would know -- didn't you keep them?
Clint: Sorry sis, I don't know of a way to tell... They can take a long time to hatch, too. Mine took forever, but one day I just went down to the kitchen and it looked like an explosion of baby mantises had occurred. The egg case looked practically the same...
Me: Yeah I guess there can be a lot of them. It will be interesting if it hatches. Was yours Chinese or something else? I think we may have seen the female who laid this one. They are pretty incredible insects.
Clint: They certainly are. Having a full grown one as a pet for a while is a neat experience, as is feeding it. There will probably be a couple hundred from one ootheca. I believe mine was chinese (if that is the green breed). Some of them are quite exotic looking.
Note: Apparently the Chinese mantis can also be green, although the ones we've seen around our house haven't been that I recall. They've been as pictured in this post. The ones I remember around my parents' house, where Clint may have caught his, were smaller and also green, and if they weren't Chinese they might have been either European or Carolina (looks like both of these species also have either a brown or green form).