Adolescent moths and butterflies, which we see as caterpillars are often found with protective stinging hairs and fibres, bodily features often containing venoms, transmitted to attackers by penetrating actions of the hair/fibre tips
Even lightly brushing up against such animals can result in dermatitis, itching and great pain, attacks and stings causing discomfort according to the species of caterpillar involved, the saddleback especially nasty, one unfortunate victim describing pain much more savage than a wasp sting for almost 3 hours.
Small caterpillars like these are difficult to spot on forest floors or amongst leaves, so great care is needed when out in the woods. Though pain and itching caused requires prompt treatment, injuries are rarely serious, though anyone with allergy problems, should be extra vigilante.
Pressing sticky tape onto the affected area, before ripping it off again to remove offending hairs or fibres is the best bet, repeating this process several times. Ice-packs over the area help to further reduce burning and itching, as does the application of a water and baking soda paste.
Saddleback Caterpillars are reddish-brown in colour, only one inch long, fleshy, spiny horns at each body end with shorter spiny horns on the sides, and that distinct green saddle-shaped mid-section coloring, with the centralized brown or purple circle are common across the USA,
They mostly appear in late summer, eating various types of tree, including dogwood, oak, plum, apple, cherry and chestnut, the end spines having those urticating hairs, which secrete that irritating venom. Contact is always very painful, leading to a rash commonly lasting for days as well as nausea and swelling, sensitive skinned individuals likely to have severe reactions.. Lovely as these creatures look, people friendly they certainly are not.