Naiads are nymphs.
These creatures are Greek figures associated with water. They were known to be beautiful women that could freely change shape and loved frolicking near water. The use of Naiads presents a constant in the poem. Wheatley claims that as long as the Naiads are frolicking, then Maecenas will see the validity of her art because there are certain constants in her work. In other words, her work is so closely linked to the epic that Maecenas can not help but support her work.