The Theory of Parasitism 



ble usurpation as an inveterate habit. More- 

 over, robbery is so incomparably easy for the 

 mother. No more cement to scratch up with 

 her mandibles on the hard ground, no more 

 mortar to knead, no more clay walls to build, 

 no more pollen to gather on hundreds and 

 hundreds of journeys. All is ready, board 

 and lodging. Never was a better opportunity 

 for allowing one's self a good time. There 

 Is nothing against it. The others, the work- 

 ers, are imperturbable in their good-humour. 

 Their outraged cells leave them profoundly 

 Indifferent. There are no brawls to fear, no 

 protests. Now or never is the moment to 

 tread the primrose path. 



Besides, your progeny will be all the better 

 for it. You can choose the warmest and 

 wholesomest spots; you can multiply your 

 laying-operations by devoting to them all the 

 time that you would have to spend on Irksome 

 occupations. If the impression produced by 

 the violent seizure of another's property is 

 strong enough to be handed down by heredity, 

 how deep should be the impression of the 

 actual moment when the Mason-bee is In the 

 first flush of success ! The precious advant- 

 age is fresh in the memory, dating from that 

 237 



