Camouflaged Lappet Moth Pupa

A large camouflaged Lappet Moth caterpillar that was found on 16Nov17 (see spotting: http://www.projectnoah.org/spottings/202616106/fullscreen) began to pupate on 18 Nov 17 (Picture 2 shows the larva in its shortened prepupal stage). As well as laying down a layer of silk, it secreted a white milky substance onto the underside of the pupal case, which by the 23rd of November, had turned the entire flat pupal case white and grey and resembled a bird dropping. On the 29th of November (11 days later) a large wet stain appeared on the top of the pupal case. Since that was definitely not normal, I opened the pupal case from the side with a scalpel. The pupa had a large spine protruding from the anterior end and bodily fluids were leaking out, causing the stain visible on the upper side of the pupal case. The larva itself was very spiny, but none of its spines were as large as the one which killed it. I kept it for several months, but no parasites emerged or were found inside. A true tragic mystery.