Basing my calculations on the respective lengths of the cocoons of the two sexes, on the thickness of the partitions and the final lid, I shortened some of these to the exact dimensions required for two cocoons only, of different sexes.
Well, these short tubes, whether of glass or reed, were seized upon as eagerly as the long tubes.

Moreover, they yielded this splendid result: their contents, only a part of the total laying, always began with female and ended with male cocoons.

This order was invariable; what varied was the number of cells in the long tubes and the proportion between the two sorts of cocoons, sometimes males predominating and sometimes females.
When confronted with tubes too small to receive all her family, the Osmia is in the same plight as the Mason-bee in the presence of an old nest.

She thereupon acts exactly as the Chalicodoma does.

She breaks up her laying, divides it into series as short as the room at her disposal demands; and each series begins with females and ends with males.