November Inchworm

2016 June 8

This inchworm was out really late in the year, it was crawling on our house siding on November 4, 2015. This was well after our first frosts, which happened a couple of weeks earlier.


If it was going to overwinter as a pupa, I would have expected it to have made a cocoon already. So it was probably going to overwinter as a caterpillar. and was crawling on our house siding looking for something to shelter under.


This picture of the head came out kind of blurry, because it wasn’t very big (less than an inch long, and quite thin) and as a result it was hard to focus precisely. But it does show the “face” markings, which could conceivably be useful for identification[1].


So anyway, this is pretty obviously the caterpillar of one of the small Geometrid moths, similar to many others that I’ve found over the years. Although, usually not this late in the season. I’m hoping that will be useful for narrowing it down as to species, because I really don’t know what kind of inchworm it is. Image search is letting me down. I posted it on BugGuide, but won’t be surprised if nobody ever identifies it.

Still, it is kind of a cute little fellow.

[Update, 2018-9-20:] Someone on BugGuide proposed an ID, after two years! It may be the Porcelain Gray, Protoboarmia porcelaria. These are found through most of North America except for the extreme north, and are know for overwintering as nearly-grown caterpillars. The caterpillars wake up in the spring, eat a bit, then pupate and emerge as moths in June.

I guess this shows that even if something doesn’t get identified right away, never give up hope.

[1] Features like face markings would be a lot more useful for identification if people actually posted pictures of more caterpillar faces. But, mostly they don’t. The vast majority of caterpillar pictures online are side shots.

2 Responses
  1. June 15, 2016

    Way cool! Fantastic camouflage, that.

  2. Rexie permalink
    November 1, 2018

    19 October 2018 one of these little kewpies was just, like out of nowhere, strolling along the edge of some papers right in front of me on my desk at work. Looks similar to the one pictured, but the one here with me has a smoother body and a darker head, and there are rosy-pink-tinges spaced along most of the length.

    It would seem to have had to travel a long way to get to where I found it, and with no particular food source I could identify. I could not put it out in the cold. I put the little one in a plastic container and brought it a calendula flower, still blooming even after some frosts. The little inchworm set to chewing on the petals, and showed a definite liking for pretty much all of the calendula flowers and second-bloom cherry blossoms I have provided — petals and centers, including pollen, as well as some of the green attached green parts. Ixnay on the snapdragon, though. As for sleeping, the edge of a drying-up viburnum leaf that was just about the exact same color made VERY good camouflage.

    Tomorrow morning will mark two weeks little inchworm will have been sojourning here. It has been officially named “Lalapua” — Hawaiian for “cherry blossom”. I spritz mist toward the inchworm bungalow a few times a day, because it so terribly dry indoors. Every day or two I swab out the castings and pick out plant material that is turning to mush. There was some concern the last few days, as “Lala” almost completely stopped eating or moving, but this morning there was a partial shed skin stuck to the little twig it had been clinging to. And those tiny little front legs are actually noticeably longer now! Then — lucky me — when I looked in with my 10X magnifier to check on my guest early this afternoon, Lala was on the move, and came over and chowed down on the shed skin!

    We’ll see how this turns out …

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