98 INSECT LIFE vii 



toward the entrance. An egg is laid on each. 

 Then the burrow has to be closed. The sand from 

 the excavation lying heaped before the cell door is 

 promptly swept out backward into the passage. 

 From time to time fair-sized bits of gravel are chosen 

 singly, the Sphex scratching in the fragments with 

 her forefeet, and carrying them in her jaws to con- 

 solidate the pulverised mass. If none suitable are 

 at hand, she goes to look for them in the neighbour- 

 hood, apparently choosing with such scrupulous care 

 as a mason would show in selecting the best stones 

 for a building. Vegetable remains and tiny bits of 

 dead leaf are also employed. In a moment every 

 outward sign of the subterranean dwelling is gone, 

 and if one has not been careful to mark its position, 

 it is impossible for the most attentive eye to find it 

 again. This done, a new burrow is made, provisioned 

 and walled up as soon as the Sphex has eggs to 

 house. Having finished laying, she returns to a 

 careless and vagabond life until the first cold weather 

 ends her well-filled existence. 



The Sphex's task is accomplished. I will finish 

 mine by an examination of her weapon. The organ 

 destined for the elaboration of her poison is composed 

 of two elegantly branched tubes communicating 

 separately with a common reservoir or pear-shaped 

 vial, whence proceeds a slender channel leading to 

 the axis of the sting and conducting to its end the 

 little poisoned drop. The dart is extremely small, 

 and not such as one would expect from the size of 

 the Sphex, especially from the effect which her sting 

 produces on crickets. The point is quite smooth, 

 without the barbs found in the sting of the hive bee. 



