More Hunting Wasps 



Two-banded Scolia has just shown us: her 

 Cetonia-grub, stung less than a millimetre 

 from the regular spot, did not become mo- 

 tionless until next day. There is no doubt, 

 judging by this instance, that the effect of 

 the virus spreads in all directions within a 

 radius of some extent; but this diffusion is 

 not enough for the operator, who requires 

 for her egg, which is soon to be laid, abso- 

 lute safety from the very first. 



On the other hand, the actions of the para- 

 lysers argue a precise search for the ganglia, 

 at all events for the first thoracic ganglion, 

 the most important of all. The Hairy Am- 

 mophila, among others, affords us an excel- 

 lent example of this method. Her three 

 thrusts in the caterpillar's thorax and espe- 

 cially the last, between the first and second 

 pair of legs, are more prolonged than the 

 stabs distributed among the abdominal gan- 

 glia. Everything justifies us in believing 

 that, for these decisive inoculations, the 

 sting seeks out the corresponding ganglion 

 and acts only when it finds it under its point. 

 On the abdomen this peculiar insistence 

 ceases; the sting passes swiftly from one 

 segment to another. For these segments, 

 which are less dangerous, the Ammophila 

 perhaps relies on the diffusion of her venom; 

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