less than one inch, brown with bright lime green band. has brown/black dot with white outline on the top and a small white dot on both head and tail. lot of legs like a caterpillar but with four antenna looking spikes covered in prickles. found in on a hosta leaf after i rubbed against it with my wrist. it left several small lumps from the prickles.
Brian, your photo is of a saddleback caterpillar.
It has poisonous spines on the four large projections (tubercles) and many smaller ones that stick out from the sides of its body. Contact with them causes a burning sensation and inflammation that can be as painful as a bee sting. The irritation can last for a day or two and may be accompanied by nausea during the first few hours. Usually the site of contact reddens and swells much like a bee sting.
A person “stung” by a poisonous caterpillar should immediately wash the affected area to remove any insect hairs and poison that remain. An ice pack will help reduce swelling, and creams and lotions containing steroids will lessen the discomfort.
The saddleback caterpillar is a general feeder. Food sources are many trees, shrubs, and grasses including apple, asters, blueberries, citrus, corn, dogwoods, elms, grapes, linden, maples, oaks, Prunus species, sunflowers and viburnums.
Sheri submitted a pic of the same caterpillar and learned they do feed in green beans and the sting hurts.