THE BEMBICENE WASPS 29 



down into it any more; then she assumes the same position 

 backwards on the hole and crams and packs the dirt down 

 with her hind pairs of legs and pounds, rubs and punches 

 it down with her abdomen; then brushes more dirt back 

 upon the depression and repeats the packing process two or 

 three times, until the fill is brought up exactly level with 

 the surface of the ground. Having finished tamping the 

 earth she begins sweeping all around, as usual, to remove 

 all traces of her nest from the surface of the ground. Her 

 conduct at this point varies with the conditions; if there 

 is a surplus of loose dirt near the site of the hole, she 

 sweeps it well away and scatters it evenly over a consider- 

 able area; if it is bald so that traces of the filled hole may 

 be seen, she sweeps other dust back over it from a distance 

 until no trace of a scar may be seen. When sweeping away 

 from the hole she begins at the outer edge of the patch of 

 dirt, faces the hole and kicks the dust back of her as she 

 moves from side to side and gradually nears the opening, all 

 the time with a stream of dirt spurting out behind her ; then 

 she backs off to the periphery of the dusty space again be- 

 fore beginning anew, scattering it further and further from 

 the nest. If, however, she is sweeping dirt toward the hole, 

 she displays far greater skill in estimating the distance and 

 the force necessary to throw the dirt in precisely the right 

 spot. She always works with the hole squarely behind her, 

 so she can throw the dirt back of her. She works fast and 

 furiously in the hot sun, brushing lightly when near the hole 

 and increasing the strength of her throw as she moves 

 further away from it, and, with wonderful judgment of 

 direction and distance of throw, hitting the region of the 

 burrow with astonishing accuracy, from various distances. 

 (See fig. 4.) She moves from side to side as she works, 

 so that her path practically describes arcs of ever-widening 

 circles the center of which is the burrow. When she has 



