The first impressions of sight, which are the most long-lived of any, shall bring back my insects to the place of their birth.

And not only will the Osmiae return, through the always open windows, but they will also nidify on the natal spot, if they find something like the necessary conditions.
And so, all through the winter, I collect Osmia-cocoons picked up in the nests of the Mason-bee of the Sheds; I go to Carpentras to glean a more plentiful supply in the nests of the Anthophora.

I spread out my stock in a large open box on a table which receives a bright diffused light but not the direct rays of the sun.

The table stands between two windows facing south and overlooking the garden.

When the moment of hatching comes, those two windows will always remain open to give the swarm entire liberty to go in and out as it pleases.