236 THE SOLITARY WASPS. 



Bometimes a wasp will save time by leaving tlie entrance open. 

 This, however, is a doubtful case rs the advantage would, per- 

 haps, be more than balanced by the exposure of the nest to par- 

 asites. The most conspicuous example that we have seen of 

 intelligence among wasps, was in that individual of Ammophila 

 that rose above her fellows by using a stone to pound down, the 

 earth over her nest. 



The general impression that remains wdth us as a result of our 

 study of these activities is that their complexity and perfection 

 have been greatly overestimated. "We have found them in all 

 stages of development and are convinced that they have passed 

 through many degrees, from the simple to the complex, by the 

 action of natural selection. Indeed, we find in them beautiful 

 examples of the survival of the fittest. 



