The puss caterpillar, or woolly slug, is the most poisonous caterpillar in the United States. Its poison is hidden in hollow spines among its hairs. This hairy caterpillar is found in the southern states, ranging west through most of Texas and north to Maryland and Missouri. It feeds on shade trees such as elm, oak, and sycamore. Puss caterpillars vary in size from 1.2 in. (32 mm) to 1.4 in. (36 mm).

See a photograph of a puss caterpillar.

Symptoms of puss caterpillar contact may include:

• Immediate, intense pain that often comes in waves.
• A swelling, itching rash of red blotches and raised ridges.
• Restlessness and anxiety.
• Nausea and vomiting.
• Fever.
• Muscle cramps.
• Swollen glands.
• Symptoms of shock.

If you come into contact with a puss caterpillar, remove the broken-off spines by using cellophane tape or a commercial facial peel, and call your health professional.