It's a bugger, obstetrics. I opened most of the cocoons. All except two were empty. The other two had chrysalises (chrysalides? not sure), which may or may not produce imagines.
In the meantime, a free-flying moth arrived in the garden, all fired up with testosterone, so I put him in the cage with Mrs Emp and in no time, they were going at it like knives.
I phoned Jon Clifton of Anglian Lepidopterist Supplies, who told me it can take up to a week before she lays her eggs.
So, think of me pacing the corridors of the maternity ward, waiting for news that mother and eggs are doing fine.