The thorax contains the muscles that make the legs and wings move. These moths have a large, heavy body, and are slow fliers. Their caterpillars, called woolly bears, have long black hairs on top and rust-colored hairs on the underside. Larvae eat leaves from the tulip tree, sweet bay, wild black cherry, ash, lilac, aspen, birch, and choke cherry. A toxin is a poison.
Some butterflies eat plants that contain toxins in order to poison their predators.
Monarchs eat milkweed for its toxic glycosides. The rate of transpiration varies as the conditions of the plant change and is controlled by the opening and closing the stomata. Many caterpillars have tubercles. For example, the caterpillars of the Cecropia and Cynthia moths have many tubercles along the body. A type species is the species of an organism from which a new genus is named.