Dickinson starts with a word from the ledger and the law court: the butterfly "obtains" little sympathy, as if sympathy were a commodity he has applied for and been refused. The situation is simple. Science speaks well of him ("favorably mentioned / In Entomology"), but ordinary opinion convicts him. He flies where he likes and wears a handsome coat, so the cautious decide he must be "dissolute." If he carried the plain badge of hard work, he would be better qualified for "Immortality." The central idea is that people mistake visible busyness for worth, and read beauty and freedom as signs of vice.
The poem's humor comes from its register. "Obtains," "favorably mentioned," "certifying" and "Entomology" belong to reports, references and official paperwork. Dickinson speaks of the butterfly as though he were a job candidate, and of immortality as something that needs a stamp of approval. The joke is that the formal record on him is fine. The unfair verdict comes from everyday opinion, which is much less careful than the Latinate vocabulary suggests.
The second stanza is where the logic goes wrong. "Because he travels freely / And wears a proper coat" sounds like a reason, but it is only a description, and the leap from description to guilt is the poem's target. "Circumspect" literally means "looking around," and the people who watch others so carefully end up "certain" without any evidence. "Proper" is nicely double-edged. It means respectable, but it also means the coat is genuinely his own, since it is his wings. The accused is guilty of nothing except being exactly what he is. "Dissolute" has the sound of loosening in it, and the word fits the way the poem pictures a free life as one that has come undone.
In the last stanza the clothing imagery turns into heraldry. A "scutcheon" is a coat of arms, and the "homely" one of "modest Industry" is a plain family crest the hard-working display like a badge. Industry is capitalized almost like a person, a virtue with its own household. Nobody is named as the industrious, though one imagines the usual ants and bees. The poem also never says whether the butterfly deserves immortality, only that "'Twere fitter" if he looked more like a worker. The comparative "fitter" may carry a faint tailoring pun after all that talk of coats, though that is my reading. There is an irony here too. The butterfly has long been an emblem of the soul and of transformation, so the creature most associated with rising into a new life is the one the diligent would turn away.
The form keeps all this light. There are three quatrains of short lines, roughly six or seven syllables each, with about three beats, so the poem moves briskly. Only the second and fourth lines of each stanza rhyme. Two of those rhymes, "sympathy / Entomology" and "Industry / Immortality," fall on weak, unstressed endings, so they land softly. The rhyme in the middle stanza, "coat / dissolute," is only a slant rhyme, and it sits exactly where the accusation is made. Maybe the sound is a little off because the charge is. Each stanza also ends on a dash, and the last one leaves the verdict hanging in the air instead of closing it.
Dickinson (1830–1886) wrote small, compressed poems, and most of them did not appear in print until after her death. This one shows how much she could do in twelve short lines. A tiny subject, an insect's reputation, is enough to question how a community decides who counts as good. It is tempting to see the butterfly as a figure for anyone whose life is more beautiful than useful, an artist perhaps, but the poem never says so. It holds its deadpan tone and lets the reader notice how silly the standard is.