Answer: allusion.
Explanation:
An allusion is a figure of speech in which the author references an object, person or event from a different context in an indirect way. It is up to the reader to make the direct connection. Usually, these references are to well-known subjects in order for the reader to be able to decipher them.
In this case, the author is referencing both the myths of Hercules and the comedies of Aristophanes. These are topics that would have been well-known by his contemporaries.
