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Promethea Moth Cocoon

4-22-14  promethea cocoon 478When a Promethea Moth caterpillar, one of our giant silk moths, is ready to pupate at the end of the summer, it strengthens the stem, or petiole, of a leaf on its host plant with silk and then attaches the silk to a nearby branch, assuring that the leaf will remain attached to the tree. (Imagine having the instinctive foresight in your youth that this caterpillar had!) The caterpillar then curls the leaf around itself and spins its cocoon inside the curled leaf. The cocoon dangles from the host plant throughout the winter and in early summer the moth emerges. Now is the perfect time for finding a Promethea Moth cocoon, as last year’s leaves are gone on most trees, and this year’s buds have yet to open. Look for a tree or shrub that has just one dead leaf hanging from one of its branches. (Cecropia caterpillars favor black cherry, poplar, ash, maple, oak and willows trees among others.)

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8 responses

  1. Claudia Wulff

    Imagine the foresight!

    I just saw a very interesting documentary on PTV about the evolution of animal and human brains. It compared the tiny brains of insects with the large brains of dolphins, elephants,chimps and humans. It mentioned, that dogs are not as smart as humans because they do not recognize themselfes in a mirrow. At what point does instinct become thinking? Has our old brain shrunk in favor of a larger new brain? From my observation it seems that way sometimes.

    April 24, 2014 at 12:43 pm

  2. Kathie Fiveash

    I believe there are five different big moths of the family Saturniidae in New England – Cecropia, Luna, Promethea, Polyphemus, and Io. When I looked up their host plants, they all are somewhat generalists, with a variety of hosts, and it looks like they all use leaves when making their cocoons. I’ve seen a few Cecropias, Lunas, and an Io on Isle au Haut, but never found a pupa. Now I know how to look! Thanks, Mary.

    April 24, 2014 at 1:42 pm


    Hi Mary,

    I took a picture of this cocoon a couple days ago. I noticed it while on my lunch walk.

    Might this be a Promethea Moth cocoon? It’s about 3-4 inches long and about 1+ inches wide.

    Thanks, June Rogier

    Sent from my iPhone


    April 24, 2014 at 1:54 pm

  4. Good tip, today, thanks! One of my most enduring memories is while standing on a rock in the middle of a river, from way up river I saw a large, fluttering object flying towards me straight downriver. It did not veer until the last few feet and went over my head – a huge cecropia moth! Wow, it was amazing!

    April 24, 2014 at 1:56 pm

    • Sounds like an incredible experience, Eliza.

      April 24, 2014 at 2:10 pm

  5. i’ve been collecting cecropia and promethea moth cocoons all winter. i think i’m addicted to finding them. i see them everywhere. have about 40 now. (hope i haven’t devastated the wild population.) Recently i have been noticing them but leaving them where they are. The cocoons i collected are out in my shed. i kept some indoors and four of them have already “eclosed” so i had two male and one female promethea’s (alas, the female emerged too late for the males) and one cecropia female flying around the house. Quite startling. A bunch were parasitized by wasps, but i’ll be checking on the ones in my shed, and when they emerge i’ll let them out to mate with whomever first arrives. i’m hoping they will emerge at the same time as the “wild” ones, then we should have an orgy of cecropian proportions!

    April 24, 2014 at 2:26 pm

  6. dellwvt

    I was puzzled by your mention of Promethea Moth at the beginning, and Cecropia at the end, so I googled “promethea and cecropia moth,” and found the following website, which has some absolutely astounding photos, including videos, of Promethea & Cecropia caterpillars at different stages of development:

    April 24, 2014 at 4:14 pm

  7. Kathie Fiveash

    WOW! Just looked at the website dellwvt posted. Exquisite, extraordinary photos and video. Thank you so much for posting!

    April 24, 2014 at 5:15 pm

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