reticulatum, based on the rusty color of the second antennal segment.

Thanks, Seth. Is that rust color something you can see from the images posted online, or just on original pics? The one I have doesn't seem to have any rust, so probably reticulatum like yours. Thanks, again.

BG info page mentions it but I can't see it in most of the photos. I just posted a new photo in reticulatum. See explanation there. Just a small trace of rusty visible.

The elytral ridges are of equal height (costae 2 and 4 would be raised in reticulatum); the interstitial cells are coarse-textured; the black areas are glossy, with a blue-black sheen (particularly visible in the second photo), and the overall shape of the elytra is more flaring, with more dramatic expansion beyond the midpoint.

The characters described in Green 1952 are very helpful for distinguishing between the 3 US species of Calopteron. In my experience, the color of antennal segments can rarely be seen in photos and is not a very helpful character.

Hopefully an editor will add this to the info page.