CHAPTER XI 

 THE SAND-LOVING AMMOPHILA 



Sphex (Ammophila) pic tip ennis Walsh. [S. A. Rohwer]. 



When the time comes for Sphex pictipennis to respond 

 to the impulse for nidification, she proceeds about her im- 

 portant business quietly and without much commotion. She 

 appears not to be especially exacting in the choice of a loca- 

 tion, as do some species of wasps, although occasionally she 

 is seen to abandon a place where she has begun a hole, and 

 seek another. Usually, however, she alights upon a suitable 

 spot, a bare area in a sunny, open field, and begins her exca- 

 vation in a matter-of-course way. With the mandibles she 

 cuts out the firm soil in the form of little chips-, walks to a 

 chosen spot about four inches away, and piles these chips up, 

 load by load, in a nice heap. So faithful is she to this habit 

 of piling her fresh dirt at a precise distance from her hole 

 that often only that has served as our clue in locating a com- 

 pleted nest. These characteristic piles of chips are easily 

 recognized, even when the holes are perfectly concealed. By 

 scooping off the surface soil in a circle of about four inches 

 radius around this pile, the burrow is almost invariably 

 brought to light. Only once have we seen an exception to 

 this habit of carrying the dirt to some selected spot : in that 

 case the ground was so dry that it was easily pulverized, and 

 as the wasp bit out each load of dirt, she stepped back an inch 

 or so from the hole, in this direction or that, and threw it 



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