Bramble-bees and Others 



edifice ends with two transversal partitions 

 and one longitudinal partition, which mark 

 out, on the same level, chambers twelve and 

 thirteen, both of which contain males. 



There is nothing more curious than this 

 mixing of the two sexes, when we know with 

 what precision the Osmia separates them in 

 a linear series, where the narrow width of the 

 cylinder demands that the cells shall be set 

 singly, one above the other. Here, the Bee 

 is making use of a tube whose diameter is 

 not suited to her work; she is constructing a 

 complex and difficult edifice, which perhaps 

 would not possess the necessary solidity if the 

 ceilings were too broad. The Osmia there- 

 fore supports these ceilings with longitudinal 

 partitions; and the unequal chambers result- 

 ing from the introduction of these partitions 

 receive females at one time and males at an- 

 other, according to their capacity. 



IS4 



