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Insect identification > Hemiptera > Harlequin bug
The harlequin bug (Murgantia histrionica Hahn). - This pest, native to Mexico and Central America, has gradually spread northward, feeding on cabbage, kale, mustard, turnip, radish and other cruciferous plants, and its present northern limits are now in New Jersey and Long Island, Ohio, Indiana, Wisconsin, Iowa, Nebraska, Colorado, Arizona, Nevada and Washington, though the insect rarely does much injury so far north.
The adults are about half an inch long, black or dark blue with bright red or orange marks, the brilliancy of the colors making the insects very noticeable and resulting in the common names "calicoback", "terrapin bug" and perhaps "fire bug" as well. They winter in the adult stage under rubbish or wherever they can find protection, though in the far South they are more or less active nearly all the time and there the nymphs are also present.
Farther north the bugs become active during the early spring and attack various wild cruciferous plants and lay their eggs. These are usually placed in clusters of about 12, in two rows, and are somewhat barrel-shaped, white, with two black rings around each, and a third ring on the upper end, being both very noticeable and distinctive.
They hatch in from 3 to 11 days according to the temperature and the nymphs suck the sap from the plants for 1 to 2 months, again according to the temperature, before becoming adult. When cabbage, cauliflower, kale, turnip, radish, etc., become available, the bugs go to these and thereafter devote their attention to these plants until late in the fall when various other kinds, such as egg plant, asparagus, tomato, beans and beets, may be attacked.