Moved from Graphoderus occidentalis.

This is G. perplexus based from the species key (Larson et al. 2001). Unlike G. occidentalis, the posterior black fascia on the pronotum (the black band at the bottom part of the pronotum) does not reach the hind margin, as shown in this image. The black band is contiguous (unseparated) with the hind margin in G. occidentalis. You may either want to move this back to genus page for now and/or request for a new species page.
Most of the Graphoderus species are very similar to each other and can be quite tricky to separate in the field.

I know, I know. I'm identifying my own photos. I should have done this before submitting this image. I checked out Hugh Clifford's book "Aquatic Invertebrates of Alberta" and there was a very good photo of this species. It is Graphoderus occidentalis. So this now needs a species page and I will wait a few days to see if it is added, and if not, I'll move it to the most appropriate page.