YES!! That's it! I found the same thing just a second ago. Yay, I'm gonna print out some pictures and show the kids![DOUBLEPOST=1423677337,1423677329][/DOUBLEPOST]Thanks ^_^
Late to the party, but my first guess would've been moth, also.
Hole looks too small for entrance AND exit, was probably exit-only, and I've also raised more than a few cecropia/polyphemus moths in my youth.