how to find best tour in ant colony optimization?

hi am working on ant colony optimization . but i dont know how to find out the best tour conducted by every ants best tour means the shortest tour conducted by a single ant among evry ants..

pls help,,,tanks in advance

[Walter Roberson]

Are you using "tour" in the graph theory sense, of a connected path between vertices, starting and ending at the same vertex, and passing though every vertex at least once (but not necessarily through every edge) ?