WASPS, SOCIAL AND SOLITARY 



to fill it. On being disturbed she assumed the most 

 comically threatening aspect, whirling around, lifting her 

 wings, and then circling about us. As soon as we moved 

 back she dashed at the grass-blade and pulled it out 

 with great energy. A few minutes later we made a similar 

 attempt, and again she frustrated our plan; but when we 

 inserted the grass-blade for the third time, the nest being 

 now half filled, she let it remain. Some hours later, 

 with this to guide us, we succeeded in tracing the nest, 

 but much to our disappointment found it transformed 

 into a banqueting hall. Scores of tiny red ants had dis- 

 covered this rich store of food. They had eaten the egg 

 and were rapidly finishing the spider. 



Twice afterward, in opening these nests, we found 

 the same ants in possession before us. It is probable 

 that they are a formidable enemy to this and other 

 species of Pompilus ; but they seem to find the spider 

 by burrowing beneath the surface, so that the elaborate 

 hiding of the nest from above cannot be meant as a pro- 

 tection from them. 



Pompilus quinquenotatus has a decided preference as 

 to the spider that she takes. While Pelopaeus and Try- 

 poxylon are entirely indifferent both as to size and 

 species, and the more nearly related Pompilus margi- 

 natus takes Thomisus, Drassus, Attus, Agalena or 



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