I had researched the other day to see how these caterpillars pupate, because I really had no idea. All I could find out was that some species go into the soil, and others roll themselves up in the leaves . I didn't know which way mine would go. This morning, I noticed one of them was resting on the floor of the large net enclosure. I kept checking on him, and by this afternoon, he was looking kind of puffy and scrunched-up. Clearly something was happening.
Working on the assumption that he didn't seem to be the leaf-rolling kind or he would have been doing it in an Ombu leaf by now, I set him in a small container with slightly moist, freshly composted soil. Sure enough, he dug down. I put the small container inside the large net enclosure.
Now, we wait.