Caterpillars in Your Yard and Garden - Page 41
Spiny oak slug caterpillars (Euclea delphinii) are present in summer and fall. They produce one to two generations per year.
The overall body color is green with spots of yellow, orange and red (usually on the top). Both edges on the top side and the lower lateral sides are covered with stiff lobes containing stinging spines. Host plants include oak and a variety of other forest trees and shrubs.
About the family
Slug caterpillars of the Limacodidae family have reduced thoracic legs, lack abdominal legs (replaced by sucking discs), and move in a creeping fashion. They are 0.4 to 1 inch long and may be oddly shaped. The head is often hidden under the thorax, adding to their sluglike appearance. The body ranges in color from dull to bright (green, yellow, orange, red and purple) and may be smooth or covered with elongated, stiff (sometimes poisonous) spines and urticating (stinging) hairs.