Albeit belatedly, I have revisited this situation. Although without a specimen in hand I cannot be 100% certain, I am sticking with C. trinervia. I do not put a lot of stock in color, as many species are variable throughout or in restricted parts of their range. Primarily I am basing my determination on general shape of the specimen, overall elytral sculpturing and, especially, that unlike C. verdigripennis it does not have the particularly well developed mesal fovea near the posterior third of the elytra. Unfortunately the specimen was not collected, as examining the antenna would make and open and shut case. Maybe you can find another.

Thanks, Richard, for your id thoughts. For the record, I forwarded your reply to Reggie Webster, who is of the opinion that this insect is not trinervia, for the reasons mentioned above, and also that the sculpturing is wrong for trinervia. Still, we will have to agree to disagree and say that without a specimen, then there can not be a positive conclusion to this. Thanks again.

I just recently posted images of both species in question. I am no expert, but based on my review of Fisher 1942 and Paeiro et al 2012, I am almost sure that I have those ID's right. I wish that top left apical spur could be seen more clearly. Also, is there any chance you have another photo, even if it is slightly out-of-focus, to see if the terminal antennomeres have yellow tips? C. trivneriva is a fairly small bronze species. Are you sure that yours is close to 15 mm? That would suggest C. verdigripennis. Lastly, I think yours has a bit too much green to be C. trinervia. Anyway, neither "side" can prove their case, but it is fun to speculate (and learn)! :)

Your mention of the foretibial spur made me take a closer look. On that basis, I'll change my mind, as from what we can see of that structure it is more acute than smoothly rounded. It surely would be nice to see the antennae up close, and if the picture were not so dark. But let's go with your suggestion, move it to C. V.

Thank you for looking in to this. Kind of a neat beetle. I believe I saw another one Sept 1st in the Bigelow Preserve on a tiny dead Red Spruce at 3000 feet but it eluded me. It can be maddening trying to catch buprestids high up in these twiggy alpine snags and thickets. Based on an incredibly small sample size of personal experience, I wonder if this species is a late season alpine/boreal specialist? Paiero et al do list from SC, but Harpootlian does not, so that far southern record might be a mistake.

If the Paiero et al. (2012) distribution map for this species did not show SC, then it would be accurate. According to Nelson et al. (2008; catalog), the closest the species comes to SC is PA! I do not imagine there is any detailed published record from SC. Obviously there was a misidentification, undoubtedly of either C. hubbardi or, more likely, C. orono.

I am less of an expert than you are, so if you want to move it to C. verdi..., then do so. I don't mind. The only other image I have is a close-up of the posterior region.