polypod larva
From ZooTerms (Dictionary of Invertebrate Zoology)
2. In parasitic Hymenoptera, it has many different forms, often unlike a normal insect.: 1. An insect larval stage found in Lepidoptera and some Hymenoptera with thoracic appendages and caterpillar-like abdominal locomotory processes (prolegs); polypodeiform; eruciform larva.