Cool Caterpillar

Anyone recognize this big caterpillar? EDIT: The mystery caterpillar of the day is a kind of Underwing moth, Catocala ilia. I feel pretty lucky to have found it, actually. Here’s more info at Butterflies and Moths of North America. It’s about 2.5 inches long, looks like bark, and when it flips upside-down to play dead, it’s got a purple banded underside. It’s pretty cool.

unknowncat04-14-10.jpgI’d like to help it make it to its next stage, but I don’t know what its larval plant is. I’m going to start with Oak, as that’s what I found it under.  EDIT: This species is an eater of Oak leaves, so that’s where I returned it to.

By the way, the picture on the left is of the caterpillar in a plastic 4-inch planter — I know it looks like water, but it’s dry, I promise.

42 thoughts on “Cool Caterpillar

  1. I’m going with something from the Underwing family (Catocala), possibly an Ilia Underwing. They have the grey plated look and colored underside with dark banding.
    I can’t find a dorsal view that’s as good as in my caterpillar guide, but here’s a good ventral view:
    http://bugguide.net/node/view/183149/bgimage
    They eat oaks. You should be able to find a bit of that around. 🙂

  2. Yeah, I narrowed it down to an Underwing after I posted the picture and updated the text but forgot to save it, so no one knew I’d made progress. Thanks for your search, though!
    Here’s the dorsal view I found at the same site.
    http://bugguide.net/node/view/946/bgimage
    After I realized it was a probably an Underwing, I let it out onto the oak tree it had been under and then went and got donuts, haha.

  3. My son just found one of these this morning; I live in Cobb County, GA. It is fascinating; when you touch it, it whips back and forth as if it’s trying to grab your finger. Looks agressive (but isn’t), and the bottom is simply spectactular!

  4. Yes, they whip like crazy — that’s quite an amazing defense mechanism they’ve got. The underside is so unexpected, given that the rest of the caterpillar is perfectly camouflaged.

  5. found one of these this morning while mowing the lawn. glad to know what it is and where to return it to. im ten and it was an awesome thing to find! scary at first but not any more

  6. Ooh, Bryce, you found an exciting caterpillar! Its defensive mechanism — that fast move it makes — is rather effective, isn’t it? Let me know about other caterpillars or cool things in nature you find — I’m very interested! And thanks so much for letting me know about your caterpillar (I’m glad you didn’t mow it!)!

  7. Sam & I found one of these awesome Underwing Moths while raking leaves today, March 30, 2012. Don’t believe I’ve ever seen one before. Couldn’t believe our eyes when it began to whip around and we saw the beautiful purple underside. We have lots of oak trees, so maybe we’ll see more now that we know what to look for. Thanks for your info on this site.

  8. Sam & I found one of these awesome Underwing Moths while raking leaves today, March 30, 2012. Don’t believe I’ve ever seen one before. Couldn’t believe our eyes when it began to whip around and we saw the beautiful purple underside. We have lots of oak trees, so maybe we’ll see more now that we know what to look for. Thanks for your info on this site.

  9. I’ve heard several reports of these lately, and my son found one a couple of days ago. I guess we’ll have a lot of Underwing Moths this year — perhaps the bats will be happy! It’s wonderful you and your grandson are outdoors together!

  10. My children just found on of these in the backyard! very beautiful colors thanks for the info this is our first time seeing one and google brought us straight to you.

  11. Vanessa, I think this is the year for these Underwing Moths — we’ve managed to locate three this year, and others are, too! Tell you children they have great eyes — those caterpillars can be hard to find!

  12. Husband and I spotted the underwing caterpillar on our farm in central Oklahoma too. Your right spooky but friendly. Put him on a big oak tree and watched him climb!

  13. Susan, I’m sorry for the delay in responding. But I’m glad you enjoyed the underwing caterpillar — they are fast little guys, aren’t they?

  14. i just cout one by it falling out of an oke tree and on to my head so i brought it to class but i’ll retern it

    • Glad to know you are sharing your discovery with others. Be sure to take some oak leaves for it until you can get it back to its natural home. 🙂

    • I’d place it under some leaf litter under a tree. It should be fine. It might stay in pupa stage for a while, but I’m not sure how long. How exciting!

    • It sounds like it’s doing just what it needs to. I’m not sure how long they stay in the pupa stage. Depending on the species, some moths emerge after days, weeks, or months. I’d just put it under some leaf litter in a safe spot. It knows what to do!

  15. is it bad that mirea just took the top leaf off and the worm started to flope around like it was pissed?

  16. Thanks for the helpful info! Our neighborhood found this interesting critter today and was able to identify it thanks to your website. We gave it a supper of pin oak leaves based on your dining recommendation 🙂

    • Hello, Chatham, NJ! Sorry for the delay in responding — it’s been a busy couple of weeks for me. I hope your caterpillar enjoyed its leaves — has it made it to cocoon stage?

  17. My daughter found one of these unusual caterpillars about 3 weeks ago. He has now been in his pupa stage for about 2 weeks. She has him in a large plastic jar with oak limbs and leaves. We all have been checking on him everyday, anxious to see him emerge. Anybody have any idea how long these critters stay in pupa?

  18. me and my girls just found 3 in a leaf pile. They scared us at first until we found this site. we put them under atree can’t wait to see what happens

  19. Dear Meredith,
    Just found one of these or what I think is one of these… It looks just like it but the underneath of it is not purple… its got like big black spots with some orange on the lower part of his belly. just making sure this is the same moth? I want to be able to provide it the best care but I want to make sure it is this caterpillar. Please let me know! Thanks! I did take some pictures but not sure how to get them to you cause I took them with my phone.

    • Ashley, I’m sorry for the delay in responding. There are a lot of Catocola (underwing) moth species out there. Did you end up finding the right ID? One of my favorite resources for identifying insects and spiders is bugguide.net. A lot of the Underwing moths have multiple host plants they like to eat — hopefully you figured out what it wanted. Generally, when I can’t fully identify a caterpillar, I just leave it where I found it and trust that it can find its food source — they have uncanny senses that draw them right to it. It’s also possible that it was ready to find a place to pupate.

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