The Hunting Wasps 



rings; four pairs of membranous legs on the 

 seventh, eighth, ninth and tenth rings; lastly, 

 a final pair of membranous legs on the thir- 

 teenth and last ring, making in all eight pairs 

 of legs, of which the first seven form two 

 vigorous groups, one of three, the other of 

 four pairs. These two groups are separ- 

 ated by two legless segments, which are pre- 

 cisely the fifth and sixth. 



Now, in order to deprive the caterpillar 

 of its means of escape, to render it motion- 

 less, will the Wasp drive her sting into 

 each of the eight rings provided with loco- 

 motory organs? Above all, will she take 

 this superfluity of precaution when the prey 

 is quite weak and small? Certainly not: a 

 single stab will be enough; but it will be 

 given at a central point, whence the torpor 

 produced by the tiny drop of poison can 

 spread gradually, with the least possible de- 

 lay, to the segments furnished with legs. 

 There is no doubt about the segment to be 

 picked out for this single inoculation : it must 

 be the fifth or the sixth, which separate the 

 two groups of locomotory rings. The point 

 indicated by rational inferences is therefore 

 also the point adopted by instinct. 



Lastly, let us add that the Ammophila's 

 266 



