236 INSECT LIFE 



XVII 



establish themselves. The wide-open entrance would 

 each time require long and painful labour, whether 

 to close it with earth or gravel, or to clear it. The 

 domicile, therefore, must be hollowed in earth with a 

 very light surface, in dry, fine sand, yielding at once 

 to the least effort of the mother, and which slips and 

 closes the entrance like floating tapestry, which, 

 pushed back by the hand, allows entrance and then 

 drops back. Such is the sequence of acts, deduced 

 by human reason, and put into practice by the 

 wisdom of the Bembex. 



Why docs the spoiler kill the prey instead of 

 paralysing it ? Is it want of skill with the sting ? 

 Is it a difficulty arising from the organisation of 

 the Diptera or from the manoeuvres of the chase ? 

 I must own, at once, that I have failed to put a 

 Dipteron, without killing it, into that state of com- 

 plete immobility into which it is so easy to plunge 

 a Buprestis, a Weevil, or a Scarabaeus, by injecting 

 a little drop of ammonia, on the point of a needle, 

 into the thoracic ganglia. It is difficult to render 

 your subject motionless ; when, it no longer moves, 

 actual death has occurred, as is proved by its speedy 

 decay or desiccation. But I have too much con- 

 fidence in the resources of instinct, — I have seen the 

 ingenious solution of too many problems, — to believe 

 that a difficulty, though insurmountable for the 

 experimenter, can baffie an insect ; therefore, 

 without casting doubt on the Bembex's capacity 

 for murder, I should be inclined to seek other 

 motives. 



Perhaps the Dipteron, so thinly cuirassed, of so 

 little substance, — so lean, in short, — could not, when 



