Cocoon above! Cocoon below — Metamorphosis

This poem describes cocoon directly, except that chrysalis takes much longer than "an hour." Dickinson was imagining herself a cocoon, to be a butterfly after an hour.

Cocoon above! Cocoon below! ¹
Stealthy Cocoon, why hide you so
What all the world suspect?
An hour, and gay on every tree
Your secret, perched in ecstasy
Defies imprisonment!

An hour in Chrysalis to pass, ⁷
Then gay above receding grass
A Butterfly to go!
A moment to interrogate,
Then wiser than a "Surrogate,"
The Universe to know!

(F.142/J.129)

[1-3] Cocoon, why hide, suspect:: Dickinson was wondering what pupa is doing in its cocoon.
[4] An hour, gay:: she wandered for an hour happily in the woods.
[5] Your secret, perched in extasy:: her secret was the extasy in defying the imprisonment; she experienced that while she tried to simulate the cocoon.
[6] Defies:: defy, to challenge to a contest or trial of skill _{(OED v.1 3)}. Defies imprisonment:: she challenged the imprisonment by trees around her.
[7] An hour in chrysalis:: she pretended to be in a cocoon for an hour. Usually the chrysalis stage takes about one to two weeks.
[9] Butterfly:: something beautiful; a new soul after the metamorphosis.
[11] Surrogate:: her old body is now the surrogate of her new soul.
[12] Universe to know:: she used her new soul to see the world.