A found poem (Letter from W.D. Fox to Charles Darwin, May 8th, 1874)

Butterflies and moths,
preserved in a book,
the great desire of his heart.
But alas!
The poor butterflies
lose a sad deal,
luster and beauty.

I have outlived almost all.
I have remembrances about me,
old-age encreeping upon me,
I had looked for its approval,
but it comes in leaps.
Does it not seem strange
how old we get?
Seems but a few years
since we were lads,
young and foolish.

How such a mind
could care for silverfish.
Do you remember Brachemis Crepitans
and our delight in finding it?
I have never seen it since,
until I saw death.
Those were the days I rejoice.