Petronilla

Perhaps it would be better to say in the entry that Petronilla is a diminutive for Petronia. In my humble opinion, that is clearer and less roundabout than saying "a feminine diminutive of Petronius". Besides, referring to Petronia instead will ultimately still refer people to Petronius, as Petronius is mentioned in the entry for Petronia. As such, it would be a "best of both worlds" kind of thing - but that's just my opinion. ;) [noted -ed]