I'd just have losing the stinger deal some amount of damage. Maybe constitution damage, so it's not trivial at higher levels.

Since regenerate is the only spell I know of that restores lost body parts, and it's 7th level, you might want to give some built-in way to regrow it.

So, scratch what I said earlier about damage/ability damage. Make it ability drain and then the stinger grows back as soon as soon as constitution is full restored (which requires magic).

And for as hard as a detachable stinger is to use at low levels, maybe it could continue pumping poison into the victim until its removed (with a DC-whatever heal check). And trying to get the stinger out of the wound could have the possibility of dealing more damage (since it's barbed) or injecting even more poison (because you accidentally squeezed the venom sack).



For anthropomorphic spiders imitating anthropomorphic ants, I've always favored that one spider that holds its "extra" set of legs up, pretending they're antennae, or that one that walk around holding a decapitated ant head in front of its face.



Velutina say they're bee-like, but you said earlier they would be hornet-like. Maybe I'm splitting hairs.