Adults have a body length of 11 to 15 mm (0.43 to 0.59 in). Appearance varies greatly.
Elytra can range from shiny black to dark brownish-gold and legs are often black or dark brown-orange with black
tarsi. Typically, the
pronotum has a black stripe running lengthwise with orange or pale yellow sides. It has also been found that some specimens of
P. alpinus have no black marking on the pronotum. Although the appearance of the pronotum is variable, the head is consistently black from in between the
compound eyes to the front of the pronotum. The
antennae are mostly black with a few orange segments closer to the head. == Range ==