Here come real stars to fill the upper skies,
And here on earth come emulating flies,
That though they never equal stars in size,
(And they were never really stars at heart)
Achieve at times a very star-like start.
Only, of course, they can't sustain the part.
In Reality… 
 Fireflies are just bugs. 
 
 Often, they’re not even glowing bugs. Most of the time, they simply look like any other beetle. 
 
 But for a moment, Frost allows the reader to disregard reality; he hides away the true nature of fireflies within parentheses.
Fireflies in the Garden