Mason bee

Bee of the family Megachilidae. Unlike honey bees or bumblebees, Osmia species are solitary. This one has been spotted entering and exiting from a small hole in a wood post. Osmia bees do not excavate their own nests but typically nest in narrow gaps and naturally occurring tubular cavities like hollow twigs, but also in abandoned nests of wood-boring beetles or carpenter bees, in snail shells, under bark, or in other small protected cavities.