what are the fieldmark differences?

Take a look at this photo for the little wood satyr. The main difference for the Viola's wood satyr is that the "underside of both wings has distinct markings; the dark postmedian line is strongly bowed." Stated from NPWRC.

Maybe Hannah or Alan will chime in. The thing that jumps out at us about the image of viola on your link is the size of the eyespots. The eyespots are almost as big as the cross section of the light brown field where they lie. In cymela they do not touch the outer edge of that field and are only about half the width of the field. But who knows if that is important??!! If you're fairly sure this is viola, then we should post a question in the forums and see if we can get some people to look through the Megisto and see what they think. Thanks for the new info.

I am certainly not sure of the ID. I didn't think they were as similar as they are. I think it would be best to get an expert to look at it.

but I see what you mean, Matthew, about these two looking different from the others posted here. I can see Opler's "strongly bowed" postmedian line on this one, but not so much on the thumbnail you linked above -the eyespots do appear stronger and larger, though.