Moth pupa case?

Moth pupa case?

Observation - Moth pupa case?. Description: I found about 10 of these large moth pupae while looking for Lizard Orchids on the Devil's Dyke near Newmarket. They are about 30-40mm long, 8-10mm in diameter and many were poking out the ground and then split open - the soil on the dyke is very compacte

I found about 10 of these large moth pupae while looking for Lizard Orchids on the Devil's Dyke near Newmarket. They are about 30-40mm long, 8-10mm in diameter and many were poking out the ground and then split open - the soil on the dyke is very compacted so it must have been a remarkable effort for the adult to wriggle up and then emerge. I have no idea what species they are I assume a large moth, maybe a hwk moth. I have kept a sample which i will try to take another, better picture of.