The Modern Theory of Instinct 



us accept as the initial prey a feeble cater- 

 pillar, paralysed with a single sting. Even 

 then that sting must not be given at random, 

 else the act would be more harmful than 

 profitable. Irritated, but not subdued by the 

 wound, the animal would but become more 

 dangerous. The dart must strike a nerve- 

 centre, probably in the middle region of the 

 string of ganglia. This, at any rate, is how 

 the present-day Ammophilae seem to go 

 to work when they are addicted to the rape 

 of frail and slender grubs. What chance 

 would the operator have of striking that one 

 particular point, if her lancet were wielded 

 without method? The probability is ludi- 

 crously remote: it is as one to the count- 

 less number of points whereof the caterpil- 

 lar's body is made up. And yet, according to 

 the theorists, it is on this probability that the 

 Wasp's future depends. What an edifice to 

 balance on the point of a needle I 



Let us go on admitting and continue. 

 The desired point is struck; the prey is duly 

 paralysed; the egg laid on its flank will de- 

 velop in safety. Is that enough? It is at 

 most but a half of what is absolutely neces- 

 sary. Another egg is indispensable to com- 

 plete the future couple and ensure offspring. 

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