How you delete and replace a frog in the middle of the pack.
First place your copied flies and frogs into the reply page then leave it till you go back and copy a frog then come back to your reply page click on what fly you want to take out.
You will find it comes up with a square of little white boxes around that said fly once that is done hit delete on you keyboard and said fly will dissappear.
Next hit paste without moving your pointer from where it was at.
You will find you will have a frog where that said fly was.
Have fun and enjoy this game.