I am informed by the Google thing that the silly odd limerick was written by W.S. Gilbert, and actually goes:

"There was an old man of St. Bees,
Who was stung on the arm by a wasp.
When asked "Does it hurt?"
He replied, "No it doesn't.
I'm so glad it wasn't a hornet."


...which may make more sense-- if it makes any sense at all.