My cocoon tightens, colors tease

My cocoon tightens, colors tease,
I'm feeling for the air;
A dim capacity for wings
Degrades the dress I wear.

A power of butterfly must be
The aptitude to fly,
Meadows of majesty concedes
And easy sweeps of sky.

So I must baffle at the hint
And cipher at the sign,
And make much blunder, if at last
I take the clew divine.