Long long ago, there was a spider who fell in love with a lady fly. Several times Mr. Spider went to Miss Fly and declared his love to him. But his proposals were spurned everytime and poor Mr. Spider waited patiently hoping that Miss Fly would change her mind one day.
One day, as Mr. Spider was passing by the house of Miss Fly, he saw her lady love humming a romantic song. Thinking that the song was addressed to him, Mr. Spider was overwhelmed with love. He could contain his emotions no longer and he proposed to her again.
Miss Fly was greatly annoyed this time.
"How dare the foolish spider propose to me again and again? Hasn't my constant rejections still given him the message that I dislike him to no end?" she thought. "Wait till I teach this creature a lesson".
So she asked Mr. Spider to wait outside her house. Then she closed the doors and windows of her home and began to boil a pot of water. After sometime, when the water had boiled enough, she opened the door and called him in.
As soon as Mr. Spider entered the house, Miss Fly threw the boiling water at him. Poor Mr. Spider jumped with pain and ran out of the house as fast as his eight legs could carry him.
"Wait till I return" screamed Mr. Spider,
"You have spurned my love, now you will taste my hatred. I and my
descendants shall be avenged upon you and yours. We will never give you a
moment's peace." And true to his word, Mr. Spider chased Miss Fly wherever he could see her. From that day, he began to hate the fly with all his heart and his descendants can still be seen to continue this tradition of animosity towards the offsprings of Miss fly.
Source: http://www.kidsgen.com/stories/general_stories/the_spider_and_the_fly.htm
