Morrison’s Pero

2017 January 11

This moth was at our porch light on June 30, 2016, and I managed to get it onto my finger for photographs. Judging from how it compares with my finger, the wingspan is a bit over an inch.


Its face is pretty typical for a moth.


The feature that caught my eye the most is the peculiar “rolled” appearance of the leading edge of the wing. In this next shot, we can see that the wings are not flat, they are turned down quite a bit at the front edge.


Between the unusual curvature of the forewing and the pronounced dark/light border running across the wings, I was able to find it in Peterson’s Field Guide to Moths. It is a geometrid moth in the genus Pero, and from the exact pattern on the wings I think the best match is Morrison’s Pero, Pero morrisonaria.

Their caterpillars are twig-mimic inchworms that feed mostly on evergreens like Balsam Fir, Pine, and Spruce, all of which we have in some quantity in our back yard. It occurs to me that maybe some of the unidentified stick-mimic inchworms I’ve posted in the past[1] could be the caterpillars of this species, but I can’t find any pictures of the caterpillars to see if they look familiar.

[1] I guess I’m not doing as bad on this front as I thought. I had the idea that there were a whole bunch of inchworms that I’d never identified, but when I went through the list, there was only the one twig-mimic inchworm that wasn’t eventually pinned down to at least the genus. Sometimes it took a while, is all.

One Response
  1. January 13, 2017

    Gorgeous. Thanks for keeping this project going. I love it.

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