The Mason-Wasps 



just as it is, after a few touches by way of 

 sweeping and cleansing. The homes which 

 I see her adopt are especially the shells of 

 Snails that have died under the stone-heaps 

 and in the low, unmortared walls which sup- 

 port the cultivated earth of the hills in 

 shelves or terraces. The use of Snail- 

 shells is accompanied by the no less active 

 use of the old cells of both the Mason-bee 

 of the Sheds and of certain Anthophorae 

 (A. pilipes, A. parietina and A. perso- 

 nata.) ^ 



We must not forget the reed, which is 

 highly appreciated when — a rare find — 

 it appears under the desired conditions. 

 In its natural state, the plant with the 

 mighty hollow cylinders is of no possible 

 use to the Osmia, who knows nothing of the 

 art of perforating a woody wall. The gal- 

 lery of an internode has to be wide open 

 before the Bee can take possession of it. 

 Also, the clean-cut stump must be hori- 

 zontal, otherwise the rain would soften the 

 fragile edifice of clay and soon lay it low; 

 also, the stump must not be lying on the 

 ground and must be kept at some distance 

 from the dampness of the soil. We see 



1 Cf. Bramble-bees and Others: passim. — Translator's 

 Note. 



i68 



