The mystery of the disappearing moth.

So...this morning I pulled back the curtain that we have hung at the backdoor to keep the draft out ( because the back door does not close properly due to the crumbling walls) and was startled to see a giant moth on the wall. It was huge and bigger than some if the birds in the garden! I grabbed a glass to catch it but it was too big for the opening and fluttered off at my attempt to trap it. I grabbed our tennis racket shaped fly electrocution device, not to kill it but to coax it down from its lofty fluttering to a level more conducive to me catching it when suddenly it disappeared. Quite literally it was there one minute and I was reaching up to it with the racket thing and the next moment it was gone and I do not remember looking away.  It completely vanished before my eyes. After a slightly comprehensive search of possible hiding places nearby I found nothing and concluded it would probably reappear at some later inconvenient moment.But even tonight, with what little light we have (due to the miserable weather) to coax it from it's hiding place, it did not reappear.I have made sure the net over the bed is gap free tonight. I don't want that thing fluttering onto my face in the dark...it was so big it would probably knock me out or at least break my nose if it landed on it!