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]
Avoidance/Control. Always wear protective clothing such as gloves and a long-sleeved shirt when working in areas heavily infested with puss caterpillars. During periods of M. opercularis abundance, children should be instructed to stay away from infested trees and shrubs and not to handle caterpillars. If necessary, heavy puss caterpillar infestations may be treated with an appropriate insecticide.
Envenomization Reaction/Treatment. (See [appendix].)
c. SADDLEBACK CATERPILLAR
(Sibine stimulea)
Identification. The saddleback caterpillar is easy to recognize since its brown sluglike body is covered mid-dorsally with markings that resemble a brown or purplish saddle sitting on a green and white saddle blanket. Upon close examination, stout spines can be observed along the caterpillar’s lateral body margin and on its four tubercles. Many of these spines are hairs that are connected at their bases with individual poison glands. Just prior to pupation and subsequent development into a moth, the caterpillar is 2-3 cm (0.8-1.2 in) long.
Distribution. In general, the saddleback caterpillar in the United States is distributed southeast of a diagonal line drawn from Massachusetts through the middle of Texas.[68]