Bramble-bees and Others 



tlon of the sexes. Lastly, at the mouth of 

 each tube, which projects slightly outside the 

 case, there is a little paper tongue, forming a 

 sort of perch on which the Osmia alights on 

 her arrival and giving easy access to the 

 house. With these facilities, the swarm 

 colonized fifty-two double-galleried tubes, 

 thirty-seven cylindrical tubes, seventy-eight 

 Snail-shells and a few old nests of the Mason- 

 bee of the Shrubs. From this rich mine of 

 material I will take what I want to prove my 

 case. 



Every series, even when incomplete, begins 

 with females and ends with males. To this 

 rule I have not yet found an exception, at least 

 in galleries of normal diameter. In each new 

 abode, the mother busies herself first of all 

 with the more important sex. Bearing this 

 point in mind, would it be possible for me, 

 by manoeuvring, to obtain an inversion of this 

 order and make the laying begin with males? 

 I think so, from the results already ascert- 

 ained and the irresistible conclusions to be 

 drawn from them. The double-galleried 

 tubes are installed in order to put my con- 

 jectures to the proof. 



The back gallery, 5 or 6 millimetres wide, 



163 



