The Life of the Fly 



glass; but the Wasps have other means of in- 

 formation in the dimness of the burrow. 

 When I produce darkness by covering the ap- 

 paratus with a screen, the murder of the tres- 

 passers is accomplished just the same. For so 

 say the police-regulations of the Wasps' nest: 

 any stranger discovered must be slain and 

 thrown on the midden. 



To thwart this vigilance, the real enemies 

 need to be masters of the art of deceptive im- 

 mobility and cunning disguise. But there is 

 no deception about the Volucella-grub. It 

 comes and goes, openly, wheresoever it will; 

 it looks round amongst the Wasps for cells to 

 suit it. What has it to make itself thus re- 

 spected? Strength? Certainly not. It is a 

 harmless creature, which the Wasp could rip 

 open with a blow of her shears, while a touch 

 of the sting would mean lightning death. It 

 is a familiar guest, to whom no denizen of a 

 Wasps' nest bears any ill-will. Why? Because 

 it renders good service : so far from working 

 mischief, it does the scavenging for its hosts. 

 Were it an enemy or merely an intruder, it 

 would be exterminated; as a deserving as- 

 sistant, it is respected. 



Then what need is there for the Voluceila 



to disguise herself as a Wasp? Any Fly, 



274 



