26o The Hunting Wasps 



the nest. It is sometimes a Green-bottle, 

 sometimes a Stomoxys, or some small Eristalis, 

 sometimes a dainty Bee-fly clad in black velvet ; 

 but the most usual dish is a slim-bellied 

 Sphaerophoria. 



This general fact, to which there is no ex- 

 ception, of the victualling of the eg^ with a 

 single Fly, a ration infinitely too small for a larva 

 blessed with a voracious appetite, at once puts 

 us on the track of the most remarkable habit 

 of the Bembex. Wasps whose larvae live on 

 prey heap up in each cell the number of victims 

 necessary for the rearing of the grub ; they lay 

 the egg on one of the bodies and close the 

 dwelling, which they do not enter again. From 

 that moment the larva hatches and develops 

 alone, having before it from the very beginning 

 the whole stock of provisions which it is to 

 consume. The Bembex form an exception to 

 this rule. The cell is first stocked with a single 

 head of game, always small in size, and the 

 egg is laid on it. When that is done, the mother 

 leaves the burrow, which closes of itself ; be- 

 sides, before going away, the insect is careful 

 to rake over the outside, so as to smooth the 

 surface and hide the entrance from any eye but 

 her own. 



Two or three days elapse ; the egg hatches 

 and the little larva eats up the choice ration 



