When it came time to giving names to the members of the Addams Family, Charles had a name for the son, Pubert. But he was asked to rename him for the TV show. So he was named Pugsley.

Those that have seen the movies may recognize Pubert, that was the name of the second son.

There are a lot of things taken directly from the strips for both the TV show and the movies, in the show, Pugsley's room is decorated with warning, and caution signs he has stolen.

Edit: i found a clearer image someone took from the copy of the November 15th, 1941 New Yorker where this strip was published originally.