Biology/Behavior. Io moth larvae feed on the leaves of a variety of plants, including corn and willow.[17] In most areas they produce only one annual generation, emerging as a moth in the spring or summer and overwintering as a pupa. In south Texas, however, two generations occur, with one developing in May-July and the second in October-December. Therefore, the urticating larval stages can be found anytime from early spring to late fall, depending upon the area of the country and climatic conditions. As with most urticating caterpillars, _A. io_ envenomizations normally occur when the victim inadvertently contacts caterpillar-infested vegetation. At the instant the victim’s skin touches this caterpillar, the spine tips break off in the skin, thus allowing toxin to flow out of the hollow spines and onto the skin. Avoidance/Control. Wear gloves, a long-sleeved shirt, and long pants when working in an infested area. Children should be warned not to handle caterpillars. If necessary, infested vegetation may be treated with an appropriate insecticide. Envenomization Reaction/Treatment. (See appendix.) b. PUSS CATERPILLAR (Megalopyge opercularis) [Illustration: (unlabelled)] Identification. The puss caterpillar is the larva of a lepidopterous group commonly referred to as “flannel moths.” In some parts of the United States the larva is incorrectly referred to as an “asp.” When fully mature, the larvae are near white to dark gray in color, 2 to 3 cm (0.8-1.2 in) long, and completely covered dorsolaterally with hairs that cause them to resemble elongate tufts of cotton. Some of the hairs are venomous, and when they penetrate the skin a “toxin” passes from an underlying gland through the hairs at the points of contact. The color variation of the larvae in this species is dependent upon larval age, locality, and time of year. In Texas, where this species is most abundant, the spring/summer generation of caterpillars is usually lighter in color than the fall generation. Distribution. This species has been recorded primarily from the Southeastern States, including Alabama, Arkansas, Florida, Georgia, Louisiana, Maryland, Mississippi, Missouri, North Carolina, South Carolina, Texas, and Virginia. Biology/Behavior. In most of the southern area of its range, the puss caterpillar is thought to have two generations per year. The first generation develops in the spring and early summer, while the second generation develops in the fall. After emerging from a cocoon and mating, the female moth lays her eggs on a suitable host plant. In a few days the eggs hatch into larvae, which develop by feeding on the leaves of a wide range of trees and shrubs. The natural enemies of the puss caterpillar usually keep its numbers under control; however, every 4 or 5 years the caterpillars become more numerous, and the number of envenomizations associated with them increases.[66]