If, after about March, a little russet-red hairy bee hums around your windows, if it explores the air vents, if you note pollen grains on your ventilator bricks and some of the holes are stopped up, consider yourself lucky: a solitary bee of the family Osmia has chosen to settle on your premises. Osmia is a very useful inoffensive bee in the garden and the orchard, where it helps with pollination. One might prefer that it builds its nest without blocking your ventilators, but it's easy to make better adapted housing. They nest in various horizontal cavities, from 5 to 10 millimetres in diameter, which they do not dig themselves. . . they readily accept artificial nesting boxes such as bunches of bamboos or of elder twigs, or blocks of wood drilled of holes of different diameters.
- J.H. Fabre, The Mason Bees