Disappearing moths????

[Sheena]

I had eight cecropia cacoons over the winter. So far three of them hatched,
so I have five left. Today I cut the last five open, and inside one of them
there was a dead caterpillar. Inside three of them were pupae. And in the
other one, there was only an empty pupa skin!!!!! I also cut open the three
cacoons that hatched, and there were only skins in those ones, so I know I
didn't have the hatched ones mixed up with the unhatched ones. So, I know
for sure I only had three moths hatch, yet I had four empty skins! How is
this possible? Is there some kind of parasite that could have eaten away the
pupa, leaving only the skin? Because I know that cacoon never hatched, but
there is just an empty skin. Any ideas?

---Sheena