@Hejor1 : do not know any moth larvae that live in a shelter fixed in a crevice like this with a partially open end. It would be interesting to see the whole larva or pupa, if you could gently prise the shelter out of the crevice, and then cut it open along its length. I suspect it is the home of a wasp or solitary bee larva maybe containing a paralysed caterpillar for food !