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Gray caterpillar - Catocala

Gray caterpillar - Catocala
Northfield, Franklin County, Massachusetts, USA
June 10, 2020
This appeared in a jar in which I had placed a few dead, broken pieces of staghorn sumac stems as pupation sites for fern-feeding sawfly larvae. Apparently it had been hiding in (or was very well camouflaged on) one of the stems.

Images of this individual: tag all
Gray caterpillar - Catocala Gray caterpillar - Catocala

Moved from Butterflies and Moths.

Thanks, I was guessing probably a Catocala... looks like both of those options feed on various rosaceous trees and shrubs, and there is hawthorn and black cherry within 20 feet of where I collected that twig.

And for what it's worth, I've found ultronia in my yard before:

Looks like...
It's an Underwing cat. These two sure look close. I wonder if, hmm.?
Catocala crataegi: - vs. - Catocala ultronia: