Can you identify this bug? And how can I prevent them from coming back?
I found large clusters of these in my newly renovated basement apartment, after being gone for a month. They were on the windowsills, in the closets, on the floor under the dishwasher, and under the oven. No one lives in the apartment. It is being used as a painting studio. There is no food in there. The oven and the dishwasher have never been used. We found no living bugs, but some sticky webbing connecting the clusters. An uncurled one is about 18 mm long. Are these the larval shells of an insect that's matured into something else? How can I prevent them from coming back?