Permutations of Sex 



Is too narrow to serve as a lodging for norm- 

 ally developed females. If, therefore, the 

 Osmia, who is very economical of her space, 

 wishes to occupy them, she will be obliged to 

 establish males there. And her laying must 

 necessarily begin here, because this corner Is 

 the rearmost part of the tube. The foremost 

 gallery is wide, with an entrance-door on the 

 front of the hive. Here, finding the condi- 

 tions to which she is accustomed, the mother 

 will go on with her laying in the order which 

 she prefers. 



Let us now see what has happened. Of 

 the fifty-two double-galleried tubes, about a 

 third did not have their narrow passage co- 

 lonized. The Osmia closed its aperture com- 

 municating with the large passage; and the 

 latter alone received the eggs. This waste 

 of space was inevitable. The female Osmiae, 

 though nearly always larger than the males, 

 present marked differences among one an- 

 other: some are bigger, some are smaller. I 

 had to adjust the width of the narrow gal- 

 leries to Bees of average dimensions. It may 

 happen therefore that a gallery is too small 

 to admit the large-sized mothers to whom 

 chance allots it. When the Osmia is unable 



163 



