Megachilidae is a cosmopolitan family of mostly solitary bees. Characteristic traits of this family include the restriction of the pollen-carrying scopa to the entire ventral surface of the abdomen and their typically elongated labra. Megachilid genera are most commonly known as mason bees and leafcutter bees, reflecting the materials from which they build their nest cells ; a few collect plant or animal hairs and fibers, and are called carder bees, while others use plant resins in nest construction and are correspondingly called resin bees. All species feed on nectar and pollen, but a few are kleptoparasites, feeding on pollen collected by other megachilid bees. Parasitic species do not possess scopae. A megachilid bee collects pollen by rapidly tapping its abdomen against the floral reproductive structures, packing the pollen into its scope.