Poisonous caterpillars come in a range of colors, shapes and patterns; some are solid green or white while others are black and adorned with brilliant splashes of red, turquoise and other vibrant hues. There are many species of venomous caterpillars, including the black moth, flannel, hag, saddleback and spiny oak. Poisonous caterpillars live around the world, including the United States, and make their homes primarily in tropical regions and warmer climates.
The Buck Moth Caterpillar is relatively large; it reaches a length of just under 2 inches when fully grown. Males and females of this species grow to approximately the same size, and bear similar physical resemblance. Both genders appear as yellow-brown juveniles, then adopt purple-black coats as adults. They are covered with numerous tiny white spots, and have tufts of neon orange hairs on their long backs. The Flannel Moth Caterpillar, in contrast, has a silky, translucent appearance. Its coat is pure white, and although angelic appearance, this insect packs a powerful poison. According to the Tampa Poison Center, the Flannel Moth can cause severe reactions to animals and humans who come into contact with their prickly venomous hairs. The Hag Caterpillar is light to dark brown in color and has nine pairs of stinging lateral processes.