Crocus Geometer

2017 February 1

Sam caught this moth for me in the yard on July 24, 2016.


We’ve seen this one before, although last time the specimen was so badly tattered that it looked quite different. It is a Crocus Geometer, Xanthotype sospeta.


Judging from the abdomen diameter and the completely not-bushy antennae, I expect that it is most likely an egg-filled female.


In spite of “crocus” being in the common name for this moth, BugGuide says that the caterpillars have been found eating willows (Salix), dogwoods (Cornus), and viburnums. Which, in this case, are mainly notable for emphatically not being crocuses.

There are actually two northern species in the genus Xanthotype (X. sospeta and X. urticaria) that are found up in this area, and they are indistinguishable without examining the genitalia under a microscope. Interestingly, they are apparently also indistinguishable by DNA analysis, which to my mind brings up some doubt that they are actually separate species at all. Or, if they are actually isolated from breeding with each other, they have only become separated really recently.

2 Responses
  1. February 1, 2017

    Why is it called a geometer?

  2. February 1, 2017

    The moths in this entire family (geometrids) are referred to as geometers because their caterpillars are inchworms.

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