The Mason-Wasps 



bringing the game; she shuts the cell with 

 a door provided with a sort of wicket, 

 through which the victualling and the lay- 

 ing 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, after- 

 wards filled with a plug, which always dif- 

 fers from the rest of the partition by pro- 

 jecting 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 em- 

 190 



