Doug Taylor, who works at the Northern Territory Park, told the prince that the witchetty grubs, found in the roots of the Acacia bush, had to be eaten head first to stop their tails moving.
The fat white worms are high in protein and are said to taste like peanut butter.
Charles picked up one of the creatures and looked as if he was about to eat it before turning to the assembled photographers and saying: "There are limits."
March 2, 2005
The BBC reports on Prince Charles (who's in Australia):