Caterpillars in Your Yard and Garden - Page 19
Prominents and oakworms
Gray furcula caterpillars (Furcula cinerea) are present from spring to fall. They produce two generations per year.
The caterpillar has a brown head and two small, brown-barbed tubercles or "horns" on the first thoracic segment. The body is green except for a brown saddle-shaped area on the abdomen. The anal prolegs are modified into a pair of long, narrow tail-like projections. Host plants are willow and poplar.
About the family
Prominents and oakworms belong to the Notodontidae family. Caterpillars have variable color patterns and body texture. Some species are smooth with fleshy humps or projections while others are hairy. Some are cryptically colored, mimicking the edge of a partially eaten, distorted leaf, while others are brightly colored and conspicuous. In some species, when the caterpillars are disturbed, they raise both ends of the body, holding onto the substrate with the four mid-abdominal prolegs and exposing glands that produce irritating acidic chemicals to ward off potential attackers. Caterpillars exhibit both solitary and gregarious behavior. Host plants include a wide variety of trees and shrubs.