I live in Guernsey Island, just off coast of Cherbourg peninsula. I have just seen a bug which looked a bit like a tiny hermit crab. It was a little larger than a grain of rice, and it’s shell or cocoon looked to be composed of tiny grains of grit and sand. A head and legs were just visible as it crawled along the top of a granite wall. Other cocoons, stationery, appeared to be fixed in crevices in the wall. Looking in books, I found it resembled a caddis fly larva – except it was not in water. I took a picture, but it is almost impossible to see the bug, as it matches its background so well. So here is my drawing. I’m intrigued as to what it might be.
You have Casebearing Moth Larva, Phereoeca fallax. They are harmless, and often feed on fallen pet hair. Your drawing is pretty great. You can see photos and get more information by visiting our clothesmoth page.