The empty Organ Pipe Mud Dauber Wasp nest popped off the wall with relatively little damage:
The open cells on the back side show the wasps don’t waste any effort on putting mud where it’s not needed:
Cracking it in half shows the rugged walls between the cell columns:
Several cells contained three or four (thoroughly dead!) spiders apiece, evidently the result of un-hatched eggs:
Each successful cell contained a brittle capsule wrapped in a thin cocoon, surrounded by fragments of what used to be spiders, with an exit hole chewed in the side:
I regret not weighing the whole affair, as all that mud represents an astonishing amount of heavy hauling and careful work by one or two little wasps!
The Smell of Molten Projects in the Morning 