MINERS 41 



the sand is drawn over it until there is no sign of 

 its situation, and the marvel is that the wasp can 

 ever find the place again. But she does, for her 

 egg hatches next day, and the fly is only sufficient 

 to feed the grub for two or three days. By that 

 time Bembex is back with another fly, and rapidly 

 excavates straight to her offspring, where she leaves 

 the new supply of food. Fabre says that she makes 

 several burrows in succession, and therefore has to 

 keep them all supplied with fresh viands. This 

 implies knowledge of their several whereabouts (all 

 in the immediate neighbourhood) and of when 

 their supplies will require replenishing. 



The flies chiefly patronized by Bembex for this 

 purpose are gadflies (Tabanus). Cattle raisers should, 

 therefore, regard Bembex as a good friend. As far 

 away as the Americas, North and South, the 

 Bembecid Wasps — some of them far superior in size 

 to the European species — show this same preference 

 for blood-sucking flies, and they have often been 

 observed to capture them in the very act of drawing 

 blood from horses. Bates relates that when on the 

 Amazons one of these flies — a Motuca — had settled 

 on his neck for a feast when a Bembex as big as a 

 hornet swooped down and captured his tormentor. 



Bates describes the mining operations of a small 

 pale-green species of Bembex (B. ciliata) which he 

 found plentiful near the bay of Mapiri, near San- 

 tarem. He says : " When they are at work, a 

 number of little jets of sand are seen shooting 

 over the surface of the sloping bank. The little 



