Is this a harlequin?

Is this a harlequin?

Observation - Is this a harlequin? - UK and Ireland. Description: There were 2 of these, near each other, just sat on the wild plant. Look exactly like a ladybird, but without any spots.

There were 2 of these, near each other, just sat on the wild plant. Look exactly like a ladybird, but without any spots.