In my grandparent's (well, really great-great-great grandfather's) 156 year old barn the ceiling is COVERED in mud daubers. These are like little balls of mud with holes in them though (I've never seen the tube ones). I'm sure some of them are as old as the barn, because the ceiling is way to high to go up and knock them down. It was really funny when we were having a party up there, and one fell down, right in my aun'ts margarita *muahahaha* Most are uninhabitied, so if you jump up and down really hard, or even better, stack up some bales of Prairie Hay and jump off them, they'll fall down. Then you get to smash them.
*Yes, this is how bored country kids spend their summers. It is actually very entertaining, and when you pull out the little wasp shell, you can scare the city family (who think they are "countery bumpeekens (as they THINK we would say)) with it.*
Sorry to hijack the thread, but it brings back memories, from last week.....