BEMBEX 289 



for I soon saw that they were catching Tse-tse fly. 

 A Bembex would alight on the sand at a spot which 

 she evidently knew, although it was indistinguishable 

 from the surrounding bare area, and commence to dig 

 away the loose sand with her powerful toothed fore limbs, 

 specially adapted for this work by a fringe of stiff hairs. 

 So rapidly does she work that the sand is thrown behind 

 her in a continuous stream, passing underneath her body 

 and falling a couple of inches behind. 



Without a pause she persists, and soon lays bare the 

 mouth of a pre-existing tunnel, at the bottom of which 

 lies her grub, hungrily devouring flies. As she works 

 in the loose sand it constantly trickles down from above, 

 but she removes it at such speed that it is thrown out 

 faster than it falls, and presently the burrow is clear and 

 she disappears from sight into it. 



Sometimes she throws up behind her enough sand to 

 block the entrance ; if she does this she usually remains 

 below for some time, but what she does down there I 

 know not. 



Presently up she comes, and, if she is careful, turns 

 away from the mouth of the burrow and throws enough 

 sand back into it to block the entrance. The reason for 

 this will be given later. 



But quite often the careless worker flies away without 

 closing the burrow, leaving the helpless grub at the mercy 

 of any marauder that discovers the opening. 



Now the busy mother has to seek food for her young, 

 and she flies round and round me as I sit on the sand, 

 apparently looking for a nice fat Tse-tse fly full of blood ! 

 Naturally she finds none, and has to take the next best, 

 but searches very carefully, coming within an inch of 

 my face and under the brim of my hat. Sometimes a 

 Tse-tse that has been sitting on my clothes takes alarm 

 and darts away, but not quickly enough to escape its 

 enemy, who pounces on it in a flash, 



20 



