The Mason Bee, Osmia lignaria, also known as the blue orchard bee, is one of many wild solitary bee species present in North America. It is friendly, and an efficient pollinator. They are called "Mason" because they construct walled-off chambers for each egg they lay. Mason bees begin working early in spring when flowers and fruit trees are beginning to blossom. After emerging from their cocoons and mating, the female Mason bees goes to work collecting pollen and nectar, while also pollinating your blossoms.