Bramble-Dwellers 



herself die in her cell rather than effect an 

 egress by forcing her way through the occu- 

 pied cells. When the cocoon that blocks the 

 way contains a dead instead of a live grub, 

 will the result be the same? 



In my glass tubes, I let Osmia-cocoons con- 

 taining a live grub alternate with Osmia- 

 cocoons in which the grub has been asphyxi- 

 ated by the fumes of sulphocarbonic acid. As 

 usual, the storeys are separated by disks of 

 sorghum. The anchorites, when hatched, do 

 not hesitate long. Once the partition is 

 pierced, they attack the dead cocoons, go 

 right through them, reducing the dead grub, 

 now dry and shrivelled, to dust, and at last 

 emerge, after wrecking everything in their 

 path. The dead cocoons, therefore, are not 

 spared; they are treated as would be any 

 other obstacle capable of attack by the mandi- 

 bles. The Osmia looks upon them as a mere 

 barricade to be ruthlessly overturned. How 

 is she apprised that the cocoon, which has un- 

 dergone no outward change, contains a dead 

 and not a live grub? It is certainly not by 

 sight. Can it be by sense of smell? I am 

 always a little suspicious of that sense of 

 smell, of which we do not know the seat and 



32 



