Is this E. harrisii or niger? Here is exact wording of the key from Downie and Arnett:

1. Antennomeres 2-3 small, together much less than length of 4. 1. E. harrisi (Westwood)

- Antennomeres 2-3 longer, 3 almost as long as 2, together slightly shorter than 4. 2. E. niger (Melsheimer)

In the species description the words about elytral punctation:
E. harrisi: elytra with rows of deep, regular punctures, intervals narrow.
E. niger: elytral punctures fine, small with intervals between them wide, flat, each with row of fine punctures.

This seems like it should be harrisii based on the description, though many BG images of niger seem to match.