Aberrations of Instinct 



last resource of an opponent at bay, I should 

 therefore like something better than the 

 absurd action of the Mason-bees. And this 

 the Pelopasus has just given us. Here we 

 have no fragrant smear left behind by the 

 victuals withdrawn, no vestige than can con- 

 ceal the absence of provisions from the 

 mother. The Spider whom my tweezers 

 are about to seize at the bottom of the cell 

 leaves no trace of her temporary sojourn, 

 nor does the egg extracted with the first 

 morsel, so that the Wasp cannot fail to be 

 apprised of the void created in her cell, if 

 she be capable of being apprised of any- 

 thing. It makes no difference; nothing al- 

 ters her habitual course of action. During 

 two days, she brings a score of items, one by 

 one, as each preceding item is removed; the 

 stubborn hunt is prolonged, on behalf of an 

 egg which has been absent from the outset; 

 and at length the door of the cell is closed 

 with the same care as under normal condi- 

 tions. 



Before considering the inferences to be 

 drawn from this odd behaviour, we will 

 record an even more striking experiment, 

 also made at the Pelopaeus' expense. I 

 have described how, when the group of 

 cells is completed, the insect plasters its 

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