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Cecropia Moths Pupating

11-11-13 cecropia cocoon dissected  056Our largest North American native moth, the Cecropia Moth, Hyalophora cecropia, spends the winter as a pupa inside a cleverly-crafted 3” – 4”-long shelter, or cocoon, which it creates and attaches lengthwise to a branch while still in its larval stage. The Cecropia caterpillar, with the silk glands located near its mouthparts, spins not one, but two silk cases, one inside the other. In between the two cases, it spins many loose strands of very soft silk, presumably to enhance the insulating properties of the cocoon. Inside the inner case, the caterpillar splits its skin and transforms into a pupa. Come spring, an adult moth will emerge from the pupal case and exit the cocoon through one end which was intentionally spun more loosely, allowing the moth to crawl out the somewhat flexible tip. (Note: dissected cocoon was not viable.)

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6 responses

  1. My son will love this post! We were talking about moths and transformation yesterday when hiking a well-known trail in New York. There was a board on an easel referencing how some pupa can remain in it’s state for up to a year before ‘hatching’. Amazing

    November 11, 2013 at 12:24 pm



     I’ve actually seen one of these hatching when I lived back in upper Michigan!

    Thanks, Judi

    November 11, 2013 at 12:28 pm

  3. Thanks for this, Mary. The photo is lovely, and it brought back memories of teaching my kids (now teenagers) about moths and butterflies. We used to bring in cocoons and chrysalises and hatch them indoors. I don’t think we ever hatched a cecropia, though. I have seen the cecropia moth only a few times, and they are spectacular.

    November 11, 2013 at 1:45 pm

  4. Jean Harrison

    Beautiful photo. I used to bring these into my bedroom as a child and wait for the moth to emerge. (I always released it, of course, but I don’t remember whether too early.) I don’t remember ever dissecting the case and seeing the two layers plus insulation. Thanks for telling us it was nonviable., I assume even before you cut it open.

    November 11, 2013 at 6:37 pm

  5. Kathie Fiveash

    I wonder how you knew it was not viable. There is a very sad description in Annie Dillard’s book Pilgrim at Tinker Creek of a cecropia moth who hatched inside a jar and was not able to properly expand its wings. I remember the vivid description of it crawling crippled away on the school driveway.

    November 11, 2013 at 8:08 pm

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