A FLY sat on the axle-tree of a chariot, and addressing the
Draught-Mule said, "How slow you are! Why do you not go faster?
See if I do not prick your neck with my sting."  The Draught-Mule
replied, "I do not heed your threats; I only care for him who
sits above you, and who quickens my pace with his whip, or holds
me back with the reins.  Away, therefore, with your insolence,
for I know well when to go fast, and when to go slow."