One day after I discovered the ”Carpet Caterpillar,” I discovered the remains of its cocoon in my living room carpet. This also explains why the caterpillar was so lethargic when I found it: a great amount of energy is expended in preparing to pupate.
Actually, there were the remains of two cocoons. Since I did not find another caterpillar, I suspect that I disrupted the one animal on two occasions. I was using boxes that had been in that spot for ages, and the caterpillar, once exposed, probably sought refuge under another box that I also eventually used.
You can even see the “trail” between the two pupal cells, a tiny trough in the carpet. Whether this represents actual damage to the fibers I have yet to find out (hey, I’m blogging, not vacuuming).