About the Blue Mason Bee
Osmia caerulescens, the blue mason bee, is a species of solitary bee from the family Megachilidae. It has a Holarctic distribution extending into the Indomalayan region, although its presence in the Nearctic may be due to human-assisted introduction.
Females of Osmia caerulescens are 10–11 mm in length, dark blue-black in color, with a metallic sheen, and sparsely covered with brown hairs with those on the abdomen forming a narrow, dense, flattened band on the hind margin of each of the segments. The dense brush of pollen-collecting scopae on the underside of the abdomen is jet black. The males are slightly smaller, 9mm, more slender in build, distinctly metallic green and clothed with pale hairs.
O. caerulescens occurs in a wide variety of habitats, including woodland and private gardens. O. caerulescens uses a variety of pre-existing cavities for nesting, such as insect burrows in dead wood, drilled borings in wooden blocks, hollow stems, drilled borings in pithy stems, burrows created by other insects in the ground, abandoned cells in exposed nests of other aculeates, cavities in banks, holes and crevices in walls, and glass tubes. The... Wikipedia →