Mary Janes and Bit-O-Honey are examples of what I think of as "convergent candy evolution." Although made by different manufacturers, from different ingredients, they have managed to produce two very similar candies - right down to the wrapper design.
Convergent evolution occurs in nature when two very dissimilar animals evolve similar structures or behavior. Birds and bats, for example, are completely unrelated - but they have both evolved very similar wing structures.
In fact I suspect that most people would be hard-pressed to explain the difference between these two candies. Much less be able to correctly identify them in a blind taste test.
And the similarity continues in that both candies are, I'm sad to report, not very popular. In fact I have heard people describe both of these candies as their pick for "worst candy."
Many people probably have early formative bad experiences with these candies. Hard taffy is not a very popular candy medium with children. It can be difficult to sell a child on a candy that is extremely hard to chew.
Add to that the odd flavors - honey and peanuts - where kids generally prefer bright fruit flavors, and you've got yourself a real loser. And yet, these two candies have persisted, clinging to their tiny market share throughout the decades. Mary Janes were developed in 1914; Bit-O-Honey in 1924.
Bit-O-Honey tends to be easier to find, particularly at Halloween. Its popularity at Halloween may seem a bit odd, but maybe because it was one of the first individually-wrapped candies. (Or maybe because it tends to be inexpensive.)
Bit-O-Honey is a honey-favored taffy studded with tiny almond bits. I prefer the taste of Bit-O-Honey, but I like the texture of Mary Janes better. Maybe someday a mad scientist will create the first Mary Jane/ Bit-O-Honey hybrid, and I'll die a happy woman.
Another clear advantage of Bit-O-Honey is that the wrapper has twists at both ends. This makes it far easier to unwrap - just grab both twists and pull to get some traction. By comparison it can be nearly impossible to get a clean unwrap on a Mary Jane. Also, the peanut oil tends to leak from the Mary Jane and permeate the wrapper with an unwholesome, oily sheen.
Mary Janes wrap a peanut butter/molasses flavored taffy around an interior dollop of creamy peanut butter. They are almost identical to Bit-O-Honeys in size, shape, and color. The wrapper is yellow with a latitudinal red stripe, compared to Bit-O-Honey's wrapper which is yellow with a longitudinal red stripe. The only real distinguishing characteristic is the interior pocket of peanut butter filling. Which, as I understand it, is a real turn-off for some people.