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INTRODUCTION TO ZOOLOGY 



Osmia. 



Osmia is another Bee of the same family as 

 Megachile, one species of which (0. tridentata) is very 

 common in the south of France. It excavates a series of 

 oval cavities in the pith of bramble stems, building up 

 between successive cells partitions made of partially masti- 

 cated pith. 



Mason Bees. 



FIG. 299. The Rose Leaf-cutting Bee. 



a, Imago ; b, one cell opened to show the grub within ; c, tunnel in a tree- 

 trunk filled by the bee with her thimble-shaped cells. 



Osmia rufa is common in England ; it utilises empty snail- 

 shells, constructing several cells within each. 



The Mason Bees (Chalicodoma) of the south of 

 France are closely allied to the Leaf-cutting Bees. 

 They construct little hard cells, about an inch deep, of a kind 

 of cement made of earth particles, causing them to adhere by 

 mixing them with saliva; occasionally the cells are strengthened 

 by the addition also of small stones. They are fixed to a large 

 stone as a base, or to a wall in some sunny spot ; as each cell 

 is finished, the bee deposits in it an egg, and then cements 

 up the opening. Eight or nine cells may be formed close 



