Northern Prairie Wildlife Research Center
Green (usually), orange, or red; in green forms, handsomely marked with yellows, oranges, reds, or combination of these. Body with numerous yellowish lobes each bearing 15 to 50 black-tipped stinging spines. Two pairs of longer lobes at tail end subtended by dense, triangular fascicle of blackish detachable ("caltrop") spines. Stinging rose caterpillar (Parasa indetermina) with lobes on fourth, seventh, and eighth abdominal segments proportionately much longer than those of spiny oak slugnearly width of body. Food: many forest trees and shrubs, especially oaks. Caterpillar: August to October; 1 generation in North.