Why does my cat lick her back legs excessively?

If you don't see any sores or anything on it's legs then it sounds like your cat has developed a bad habit. I had a cat once that sucked it's tail. Try to get the cats attention onto something else, toss a toy to your cat when you see it going to start licking.

We have a cat that licked her fur in parts until it was raw. Turned out to be an allergy to certain foods. The problem was solved, cats do not usually lick out of boredom there is often a reason.