The result surpassed my hopes.
With both these Osmiae, the division of the gallery is the same as with the Three-horned Osmia.

At the back are large cells with plentiful provisions and widely-spaced partitions; in front, small cells, with scanty provisions and partitions close together.

Also, the larger cells supplied me with big cocoons and females; the smaller cells gave me little cocoons and males.

The conclusion therefore is exactly the same in the case of all three Osmiae.
These conclusions, as my notes show, apply likewise, in every respect, to the various species of Mason-bees; and one clear and simple rule stands out from this collection of facts.

Apart from the strange exception of the Three-pronged Osmia, who mixes the sexes without any order, the Bees whom I studied and probably a crowd of others produce first a continuous series of females and then a continuous series of males, the latter with less provisions and smaller cells.