The figure of speech is allusion.
Allusion makes a reference to a place, person or event. It can be real or imaginary, and it can be direct or be inferred and broaden the reader's understanding.
Allusions engage the reader and help the reader remember the message or theme of the passage, it also allows the writer to give an example or get a point across without going into a lengthy discourse.
Allusions convey a great deal of information in just a few words.
But, because allusions make reference to something other than what is directly being discussed, you may fail to understand it if you do not know the reference point.
