SeasonalityAdults have been collected in Alberta from late May to late June.
IdentificationAdults: 8.7-9.4mm in length. Dorsal surface usually pure black, sometimes with a slight violet hue on head and pronotum. Pronotum wider at base than at apex which help to easily distinguish it from C. niger. The basal impressions of the pronotum a moderately punctate with the rest of the base being only sparsly punctate; spare punctuation on both lateral line and median line, rest of disc with only a few scattered punctures. The second interval of the elytra tends to form irregular transverse rows of two to three punctures, with rows being separated from each other by a distance of approximately half the width of the interval. Adapted from Bell 1960 and Lindroth 1963.