Comment by rottendoubt

Ya, I'm wondering that myself. Or it could mean that Pandarus gave Menaleus a way for Menaleus to identify himself (Menaleus) to others. If so, then it could be something unique to Menaleus such as his finger print. Menaleus could use his finger print as an identity check and Pandarus would have no way to remember Menaleus' finger print.