28 WASP STUDIES AFIELD 



food for their young. In contrast to this we see the final or 

 permanent closure which is made only at the end of the 

 larva's feeding period. The contrast in the methods of ef- 

 fecting the two closings will be at once apparent. 



When the wasp has finished feeding the larva, she emerges 

 from the open hole but does not turn around and go right 

 back in, head first, as previously. Instead of going in and 

 kicking the dirt up from the lower part of the channel, she 

 begins scratching and kicking the loose dirt from the sur- 

 face into the hole behind her, moving forward as she does 





FIG. 4. Bembix nubilipennis filling her burrow. Note the brush-like 

 forelegs sweeping the soil under the body, and the accuracy of her 

 aim. Natural size. 



so until she is two or three inches away from it. Then she 

 runs to the hole, peeps in, turns around and backs in, kick- 

 ing, scratching, clawing and crowding the dirt deeper down 

 into the hole and out of sight. Then she comes out and 

 exactly repeats the whole performance several times, each 

 time beginning at the margin of the burrow to scratch the 

 soil back in, and working gradually outward with her face 

 away from the opening. (Fig. 4.) Thus she continues 

 until the hole is filled so near the top that she cannot back 



