654 Reflexes, Instincts, and Intelligence 



surroundings. The same thing may i,e seen when a number of social wasps 

 work together to replace the roof of their nest when it has been torn off. 



"An instance of the second class is seen in one of our examples of Pom- 

 piliis marginatus. This species, while searching for a nesting-place, leaves 

 its spider l\ing on the ground or hides it under a lump of earth, in cither of 

 whicli ]iositions the booty is subject to the attacks of ants; the wasp in ques- 

 tion improved upon the custom of her tribe by carrying the spider uj) into a 

 jjlanl and hanging it there. We have now and then seen a queen of Polistes 

 jusca occupy a comb of the previous year instead of building a new one for 

 herself, showing a better mental equipment than her sisters who were not 

 strong-minded enough to change their ways and so built new nests along- 

 side of unoccupied old ones which were in good condition. In Bembe.x 

 society it is good form to close the door on leaving home, but sometimes a 

 wasp will save time by leaving the entrance open. This, however, is a 

 ■doubtful case, as the advantage would, perhaps, be more than balanced by 

 the exposure of the nest to parasites. The most conspicuous e.xample that 

 we have seen of intelligence among wasps was in that individual of Ammo- 

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

 over her nest. 



"The general impression that remains with us as a result of our study of 

 tJiese activities is that their complexity and i)erfection have been greatly over- 

 estimated. We have found them in all stages of dcve!oi)ment and are con- 

 vinced that they have passed through many degrees, from the simple to the 

 complex, by the action of natural selection. Indeed, we find in them beau- 

 tiful exam])lcs of the survival of the fittest." 



In a short note pulilished after the issuance of their book, the Peckhams 

 describe an e.xpcriment with a Sphex whose results to their minds plainly 

 show the tempering of the Sjjhex instinct by a certain degree of intelligence. 

 Fabre once experimented on a Sphcx, taking advantage of the moment that 

 the wasp was out of sight below to remove her prey to a little distance with 

 the result ihat when the wasp came up she brought her cricket to the same 

 spot and left it as before, while she visited the interior of the nest. Since he 

 repeated this experiment about forty times, and always with the same result, 

 it seemed fair, says the Peckhams, to draw the conclusion that nothing less 

 than the performance of a certain series of acts in a certain order would 

 satisfv her impulse. She must jilace her prey just so close to the doorway; 

 she must then descend and examine the nest, and after that must at once 

 drag it down, any disturbance of this routine causing her to refuse to pro- 

 ceed. 



"We recentlv found a Spliex ichueunwnea at work storing her nest," 

 continue the Peckhams, "and thought it would be interesting to pursue 

 Fabre's method and find out wl'etler she were equally persistent in follow- 



