Identity of construction is maintained even in details which I had at first regarded as a feat peculiar to the Osmia. Let us recall her compartment-building secret. If the reed be of middling diameter, the cell is first stocked with provisions and next bounded in front with a partition run up then and there, without any pause in its construction. If the reed, without being excessively wide, be of a certain thickness, the Osmia, before stowing away the victuals, gets to work on the front partition, providing it with an opening at the side, a sort of service-hatch, through which the honey is more easily discharged and the egg more easily placed in position. Well, this secret of the service-hatch, which was revealed to me by the glass tube, is as well-known to the Odynerus as to the Osmia. She, too, in the bigger reeds, finds it to her advantage to close the larder in front before bringing the game; she shuts the cell with a door provided with a sort of wicket, through which the victualling and the laying are done. When everything is finished inside, a plug of mortar closes the hatch. I did not of course see the Odynerus working at her partition with its wicket-door, as I saw the Osmia performing in my glass tubes; but the work itself speaks quite plainly of the method followed. In the centre of the partitions in the medium reeds there is nothing in particular to be seen; in the centre of the partitions in the larger reeds there is a circular aperture, afterwards filled with a plug, which always differs from the rest of the partition by projecting inwards and sometimes differs in colour. The thing is obvious: the small partitions are made in one spell, whereas the work on the larger ones is interrupted and then resumed. As we see, it would be pretty difficult to distinguish the Odynerus’ nest from the Osmia’s, if our enquiries were confined to the cells. One characteristic, however, and not the least curious enables an attentive eye to tell the owner without opening the reed. The Osmia closes her dwelling with a thick plug of earth similar in nature to that employed for the partitions. The Odynerus, it goes without saying, does not neglect this means of defence: she, too, makes a solid stopper; but to the unsophisticated method of the Osmia she adds the resources of a more highly-finished art. Over her earthen stopper, a thing liable to be spoilt by frost and damp, she spreads, on the outside, a good thick layer of a composition of clay and chopped-up woody fibres. It matches the red wax with which we seal the corks of our bottles.