I've only seen illustrations of urticating bristles, but I also didn't know what setae looked like under magnification. Googled it, of course, & now I don't know if I'm looking at finely plumose setae or urticating bristles. The density of the projections on UBs seems to be quite a bit more sparse with a greater ratio base:tip width than what we see here.
@HybridReplicate Ah.... you know, I think you're right about this. Urticating setae seem to have more spine-like projections than these. I've never magnified them before either. So these may just be regular plumose. But I definitely have some urticating in my thumb, though! It's driving me insane! Do I dare mess with that exo some more just to find the real deal? Lol