If anyone decides to leave the moth cage open over night, dont be supprised if your newly hatched giant moths poo brown staining liquid all over your cream walls.
I had some what I thought were infertile atlas moth cocoons strung on a branch, and was in the process of chucking them out, so I had this branch on top of a tank in my room. And last night one of them hatched! Although, no brown liquid as of yet
The only time I have found them to exude that liquid is when you attempt to handle them.
Many of my moths did that- I think I even had the 'pleasure' :? of seeing it some times... I would presume it's the 'meconium' (anyone who works with drosophila will know what this is) - it's basically the first excretion of all the waste products accumulated during metamorphosis - i.e. nothing to worry about