Sunday, August 21, 2011

Jewel Case

I found this neat little thing hanging from a tree branch in the woods. At first I thought it was the leftovers of a spider’s meal, but on closer examination it appeared to be some type of case or cocoon.

It’s certainly not very large. I noticed it rocking in the breeze at the end of a stout length of silk. The tether wasn’t at all sticky and slid cleanly across my hand as I steadied the object for a few photos.

I’m not sure what this thing is. If there had been more than just the one, I would have opened it to have a look inside. Of course, it’s possible that there were hundreds hanging from the trees and I only saw the one. It could be an egg case or a cocoon or poop or a Fairy Jewel or just an oddly shaped collection of debris. I’m betting there’s something alive in there.

The consistency of the thread and the method of attachment to the object suggest that this is its proper arrangement. I know that placing eggs at the end of a stalk or line is a survival strategy used by several insect species. I also vaguely remember many years ago reading about something similar to this. Even if I don’t find out what it is, I enjoyed getting to see the pretty little gem.


  1. I see these a lot, Steve. They are the cocoons of ichneumon wasps which have parasitized a caterpillar. Sometimes, if you follow the thread, you'll find what's left of the host. Check the images of subfamily Campopleginae at for lots of examples. Do you have _Tracks & Sign of Insects and Other Invertebrates_ by Charley Eiseman and Noah Charney? If not, I highly recommend it for identifying things like this. The entry for these there suggests the coloration is meant to imitate bird droppings, to avoid predation.

  2. Hi Steve ...I think it is a Fairy jewel... I think it would make a great necklace bead myself! : }}}
    They have used moose poop for beads and sold them so, maybe a little shellac and you coulds have a new business!! lol

  3. Thanks for the information, Troy. I got myself a copy of the Eiseman and Charney book about three months ago, but haven't had a chance to read it. As I frequently tell people, field guides don't do you a bit of good if you don't get them out and use them.

    Hi, grammie g. I thought the same thing about the necklace.

  4. Oh! I'm so glad someone was able to ID that. Very cool.

  5. Hi, Katie. It is pretty amazing. I wish it was larger.

  6. Fascinating! Thanks Steve for the interesting post and thanks Troy for the ID.