Frail Travellers, deftly flickering over the flowers;
O living flowers against the heedless blue
Of summer days, what sends them dancing through
This fiery-blossom’d revel of the hours?

Theirs are the musing silences between
The enraptured crying of shrill birds that make
Heaven in the wood while summer dawns awake;
And theirs the faintest winds that hush the green.

And they are as my soul that wings its way
Out of the starlit dimness into morn:
And they are as my tremulous being—born
To know but this, the phantom glare of day.

Siegfried Sassoon

http://www.poemhunter.com/poem/butterflies-2/