Spider Skeltons

   What happens to indoor spider corpses? The number of spiders I have seen does not match up with the amount of dead spiders I have not seen. Where do those sneaky little guys go to die? Someone told me that they crawl back into the walls (which they insinuated is where they come from). I don't know if I was just being duped, but where else could they go? Do they disintegrate? That doesn't sound like science to me. Supposing thats a legit theory, if the walls were to be broken down, would I find them insulated with spider skeletons? That, my friends, would be some serious witchcraft!