WASPS 211 
hungry for the juice, but apparently afraid to 
begin feeding on it; they were standing round in 
a compact crowd, the hindmost pressing on and 
crowding over the others: but still, despite the 
pressure, the foremost row of flies refused to 
advance beyond the rim of the eaten-out part. 
From time to time one of a more venturesome 
spirit would put out his proboscis and begin 
sucking at the edge; the slight tentative move- 
ment would instantly be detected by a wasp, and 
he would turn quickly round to face the presump- 
tuous fly, lifting his wnigs in a threatening manner, 
and the fly would take his proboscis off the rim of 
the cup. Occasionally hunger would overcome 
their fear; a general movement of the flies would 
take place, and several would begin sucking at the 
same time; then the wasp, seeming to think that — 
more than a mere menacing look or gesture was 
required in such a case, would start up with an 
angry buzz, and away the whole crowd of flies 
would go to whirl round and round in a little blue 
cloud with a loud, excited hum, only to settle 
again in a few moments on the big yellow pear 
and begin crowding round the pit as before. 
Never once during the time I spent observing 
them did the guardian wasp relax his vigilance. 
When he put his head down to suck with the others 
his eyes still appeared able to reflect every move- 
ment in the surrounding crowd of flies into his 
little spiteful brain. They could crawl round and 
crawl round as much as they liked on the very 
