THE MINERS 273 



The solitary wasps, having to search out 

 a new place for each cell, and being also 

 obliged oftentimes to go far for their prey, 

 find it necessary to exercise both observa- 

 tion and memory, and that is doubtless 

 the reason they have become so very 

 skilful in finding their way to a given 

 spot. Each nest made presents a new 

 problem, and as long as the wasp has to 

 solve these problems by its own unaided 

 skill there is little danger of its de- 

 generating into a mere mechanical, 

 worker. The enforced exercise of"^'^" 

 its faculties doubtless has been the 

 means of developing them, and will be 

 the means of continuing their develop- 

 ment. 



The intelligence of the sand-wasps in 

 closing their burrows when they leave 

 them is certainly of a high order. 



Ammophila stores her caterpillars in a 

 pocket at the end of her rather short tun- 

 nel, and when she leaves her nest she is 



