harlequin bug

noun
1.
a black stink bug, Murgantia histrionica, having red and yellow markings, that feeds on cabbages and other cruciferous plants.
Also called cabbage bug, calicoback, calico bug, harlequin cabbage bug.
Origin
1865-70, Americanism
British Dictionary definitions for harlequin bug

harlequin bug

noun
1.
a brightly coloured heteropterous insect, Murgantia histrionica, of the US and Central America: a pest of cabbages and related plants: family Pentatomidae