I saw this last night on one of my female hissers. I wasn't able to stick around and watch long enough, but she is perfectly fine this morning and the protrusion has gone away. So yeah, I'm just really curious on what was going on.

Could be the eggcase, she is about to go to the bathroom, or she is ready to mate.

Let's see... those paired yellow things closely resemble eggs, but they look really far apart, which doesn't seem good. I'm pretty sure it's something to do with her ootheca. When did you see this, and do you know if she's already mated? I think she's aborting an ooth, but plain and harmless air-drying/rotating is a possibility. I don't like the looks of that big air bubble (?) either.If it is an abortion, the cockroach should get the egg case out alright and not be harmed.

Looks like what you see when the ootheca goes from the ovaries and is transferred into the brood chamber. Nothing to worry about.

Ah. Thanks. I don't see any dropped/aborted ooth's around in there, so she was probably just rotating it.