You might be a sci-mom if you take your kid to the fair and all you can think of as she crawls through the Kiddiepillar is, “Is that a vulva? Cloaca? What do you call the back end of a caterpillar?”
And then you go look it up. It’s technically the caterpillar’s anus.
It’s not too far off either. Check out this figure from Caveney et al from The Journal of Experimental Biology (and a paper all about skipper caterpillars that can shoot their poop “over distances many times their body length”):
Did you know their poop is called “frass”? No? You didn’t know that? Oh, well, now you do!