UNSEEN PROSE AND POETRY
Read the poem and answer the question
As they trooped off down the field with their sullen dogs, the farmer started the tractor up and the cutter blade blurred into life
Left alone, Grooby sank into a shocked stupor. His mind whirled around like a fly that dared not alight. A blank vacancy held him. He seemed unable to move, even to wipe away the sweat that collected in his eyebrows and leaked down into his eyes. He sensed that the sun had settled over the earth, so that the air was actually burning gas. He watched the tractor dwindle in the bottom of the field, as if it were melting into a glittering muddle in the haze.
The expression ''like fly that dared not alight'' is a/an