I'm currently working on expanding the Dieunomia species guide of DiscoverLife to include Western species, and I've run into a rather problematic species: D. mesillae. At the NMNH I have found only the type (male). I've inquired about specimens at several institutions, but it seems that there aren't any other specimens of this species around; according to DiscoverLife, there are only three state records from CO, NM, and TX.
The male itself appears very similar to that of D. apacha, which I have four specimens of, to the point that I do not feel confident separating the two species. While a dissection could prove helpful, I cannot perform one as I only have access to the type. I have also referenced Blair & Cockerell 1935, which echoes my observations in suggesting that the D. mesillae type may be the male of D. apacha....
I was hoping that someone on beemonitoring might be able to provide some insight on this rather tricky species, either in reference to its identification or possible taxonomic issues involving D. mesillae. Any help would be appreciated. Thanks.