454 
DISCURSIVE NOTES ON THE 
the large larva inside. Presently, you hear her pounce on 
such a one with a quick rush ; there is a short, high-pitched 
buzz, like a squeal, from the unfortunate fly as it is stung ; and 
if you are quick with your eyes, you will see the Bembex dart 
away, holding the paralysed fly between the thighs of her 
middle pair of legs. She alights at a spot where the bare 
sand shows to you no difference from the surrounding area ; 
but she knows it, for did she not take great pains to cover up 
the mouth of the burrow that is there before she went away, 
to obstruct the thieving Idia, which you may see hanging 
round, a little distance off ? She alights on the sand, holding 
her prey between her thighs, and without a moment’s pause 
she begins to dig with her powerful fore-limbs, furnished 
with strong bristles. But dig is a feeble word for the energy 
displayed. The sand is hurled backwards by the rapid 
movements of her fore-limbs, working so fast that a con- 
tinuous shower of sand passes under her body to fall several 
inches away. 
As she digs, the loose sand keeps falling in ; but she per- 
severes until the opening is clear. Occasionally such a quantity 
has to be dug out that it accumulates in a little heap behind 
her and begins to trickle down again. So she begins at the far 
side of the pile and w T orks her way forward, right through it, 
until the mouth of the burrow is clear, when down she goes, 
never having let go for one moment of her precious fly. The 
waiting Idia seizes this opportunity to approach nearer, and 
waits at the very brink of the hole for the critical moment. 
Out comes the Bembex ; and if she is a careful worker, turns 
round and throws enough sand backwards to cover the mouth 
of the burrow before going off to seek fresh food for the hungry 
larva inside. This is Idms chance ; and with laughable eager- 
ness it attempts to penetrate into the burrow, scrambling 
in such haste that often it literally tumbles head over heels. 
No matter, there is need for haste ; for who can tell at what 
moment Bembex may return again ? So the little fly searches 
feverishly for some crevice which the Bembex may have left 
uncovered, that it may penetrate down the deep burrow and 
lay its eggs there. Often the Bembex has carefully rendered 
this impossible, and her sudden return necessitates hurried 
