232 THE WONDERS OF INSTINCT 



bottom determined by the ordinary length of a cell. The 

 wad is not a complete round ; it is more crescent-shaped, 

 leaving a circular space between it and one side of the 

 tube. Fresh layers are swiftly added to the dab of clay; 

 and soon the tube is divided by a partition which has a 

 circular opening at the side of it, a sort of dog-hole 

 through which the Osmia will proceed to knead the Bee- 

 bread. When the victualing is finished and the egg laid 

 upon the heap, the whole is closed and the filled-up par- 

 tition becomes the bottom of the next cell. Then the 

 same method is repeated, that is to say, in front of the 

 just completed ceiling a second partition is built, again 

 with a side-passage, which is stouter, owing to its dis- 

 tance from the center, and better able to withstand the 

 numerous comings and goings of the housewife than a 

 central orifice, deprived of the direct support of the wall, 

 could hope to be. When this partition is ready, the pro- 

 visioning of the second cell is effected; and so on until 

 the wide cylinder is completely stocked. 



The building of this preliminary party-wall, with a 

 narrow, round dog-hole, for a chamber to which the 

 victuals will not be brought until later is not restricted 

 to the Three-horned Osmia; it is also frequently found 

 in the case of the Horned Osmia and of Latreille's Osmia. 

 Nothing could be prettier than the work of the last- 

 named, who goes to the plants for her material and fash- 

 ions a delicate sheet in which she cuts a graceful arch. 

 The Chinaman partitions his house with paper screens; 

 Latreille's Osmia divides hers with disks of thin green 

 cardboard perforated with a serving-hatch which remains 



