Hind leg detail: Using the criteria listed by Dr. Fisher here, for separating H. fusca from H. abdominalis, we believe this is Holcocephala fusca, subject to the disclaimer mentioned by Dr. Fisher.
On this specimen, the hind tibia is about 16% broader than the hind femur and the hind basitarsis is slightly smaller (3%) than the hind femur. For H. abdomenalis both should be 35% larger. The first flagellomere of the antenna (see image of antenna detail) does not appear to be distinctly broader in middle with a spindle-shape: Rather it more nearly appears elongate and parallel-sided. Without seeing images of the antennae of the two species side-by-side, this is a judgement call. In describing this specimen as either dark or light, I would say dark. Again this is a judgement call without direct comparison of the two species. Confirmation/correction would be appreciated. In the absence of correction, the images of this and the following male will be moved to the H. fusca page.