The Theory of Parasitism 



robbed their neighbours with gusto, when oc- 

 casion offered, since the origin of their respec- 

 tive races, and who are working industriously 

 to create a parasite happy in doing nothing. 

 Have they succeeded? No. Will they suc- 

 ceed? Yes, people maintain. For the moment, 

 nothing. The Osmise and Chalicodomae of 

 to-day are what they were when the first 

 trowel of cement or mud was mixed. Then 

 how many ages does it take to form a para- 

 site? Too many, I fear, for us not to be 

 discouraged. 



If the sayings of the theorists are well- 

 founded, going on strike and living by shifts 

 was not always enough to assure parasitism. 

 In certain cases, the animal must have had to 

 change its diet, to pass from live prey to vege- 

 tarian fare, which would entirely subvert its 

 most essential characteristics. What should 

 we say to the Wolf giving up mutton and 

 browsing on grass, in obedience to the dic- 

 tates of idleness? The boldest would shrink 

 from such an absurd assumption. And yet 

 transformism leads us straight to it. 



Here is an example: in July, I split some 

 bramble-stems in which Osmia tridentata has 

 built her nests. In the long series of cells, the 

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