Megalopyge opercularis

The moth Megalopyge opercularis has numerous common names, including southern flannel moth for its adult form, while its larval form is known as the puss moth, puss caterpillar, tree asp, asp caterpillar, and Trump caterpillar.

Description

M. opercularis is visually striking in both larval and adult forms.

Larva

The inch-long larva is generously coated in long, luxuriant hair-like setae, making it resemble a tiny Persian cat, the characteristic that presumably gave it the name "puss." It is variable in color, from downy grayish-white to golden-brown to dark charcoal gray. It often has a streak of bright orange running longitudinally. The 'fur' on early-stage larvae is sometimes extremely curly, giving the larva a cottony, puffed-up look. The body tapers to a tail that extends well beyond the body, unlike its relative M. crispata. The middle instar has a more dishevelled, 'bad-hair-day' appearance, without a distinctive tail.

The 'fur' of the larva contains venomous spines that cause extremely painful reactions in human skin upon contact. The reactions are sometimes localized to the affected area but are often very severe, radiating up a limb and causing burning, swelling, nausea, headache, abdominal distress, rashes, blisters, and sometimes chest pain, numbness, or difficulty breathing. Additionally, it is not unusual to find sweating from the welts or hives at the site of the sting. Ironically, the resemblance of the larvae to soft, colorful cotton balls encourages people to pick them up and pet them.