Found under a rock in an open Lenga forest at El Progreso ranch. Overall length was approximately 5cm. The construction was very fragile with the consistency of tissue paper. Inside the opening there were about 8 hexagonal cavities.
On cultivated Borago officinalis.
Potter wasp larva nest is my best guess, though I don't know the size of their larvae. This nest is tiny...see 3rd photo for size reference.