The pictures above show a Mason Bee House made using a planked wooden frame, stuffed with various sized bamboo stems.
Mason bee is a general term for certain species of bees in the family Megachilidae, most appropriately restricted to the genus Osmia, such as the Orchard Mason bee (Osmia lignaria), the blueberry bee (Osmia ribifloris), and the hornfaced bee (Osmia cornifrons). They are named from their habit of making compartments of mud in their nests, which are made in hollow reeds or holes in wood made by wood boring insects. Unless of course you make your own nest for them with drill bits and blocks of wood. Mason bees are increasingly cultivated to improve pollination for early spring fruit flowers. They are used sometimes as an alternative, but more often as an augmentation for European Honey bees.
Unlike Honey bees (Apis), Mason bees are solitary; every female is fertile and makes her own nest, and there are no worker bees for these species. Solitary bees produce neither honey nor beeswax. They are immune from acarine and Varroa mites, but have their own unique parasites, pests and diseases.