XI THE SCIENCE OF INSTINCT 151 



with entire immunity. This striking result is caused 

 by the mother laying her egg in one particular spot. 

 I have already told how S. flavipennis glues her egg 

 on the cricket's breast, rather on one side, between 

 the first and second pairs of feet. S. albisecta chooses 

 the same place, and S. occitanica an analogous one, 

 rather further back toward the base of one of the 

 large hind thighs, all three thus evincing admirable 

 knowledge as to where the egg will be safe. 



For consider the ephippiger shut in the burrow. 

 It is on its back, absolutely incapable of turning 

 over. Vainly does it struggle ; the irregular move- 

 ments of its feet are useless, the cell being too wide 

 for them to gain support from the walls. What do 

 the victim's convulsions matter to the larva ? It is 

 on a spot where it cannot be reached by tarsi, 

 mandibles, ovipositor, or antennae — a point absolutely 

 motionless, where there is not even a shudder 

 of the skin. There is entire security unless the 

 ephippiger can move, turn, and get on its feet, and 

 that one condition is admirably guarded against. 



But with several, all in the same degree of par- 

 alysis, there would be great risk for the larva. 

 Though there would be nothing to fear from the 

 first insect attacked, as the larva is out of its reach, 

 there would be peril from the neighbourhood of the 

 others, which in stretching out their legs hither and 

 thither might strike it and tear it up with their spurs. 

 Perhaps this is why S. flavipennis, which heaps three 

 or four grasshoppers in one cell, almost entirely 

 paralyses them, while S. occitanica, providing each 

 burrow with a single victim, leaves great power of 

 motion to the ephippiger, simply preventing change 



