Identifying Rhyme Scheme in Poetry

Consider the following excerpt from a poem:

In the cool of the evening air, the shadows linger low,
Where whispers mingle with the softest sighs,
The twilight blooms in hues of dusk, a fleeting show,
As fireflies dance beneath the darkening skies.

Based on the structure and form of this stanza, what poetic device is predominantly being employed to enhance the imagery and musicality of the poem?