Line art illustration of a caterpillar (moth or butterfly larva) labeling prolegs (fleshy stubs, or leglike appendages) on abdominal segments 3 to 6 and also showing the rear end proleg.

The number and location of prolegs helps to distinguish between insects that resemble caterpillars and the type (e.g., family or subfamily) of caterpillar. Credit: Integrated Pest Management for Citrus, 3rd ed. University of California ANR 3303.
Line art illustration of a caterpillar (moth or butterfly larva) labeling prolegs (fleshy stubs, or leglike appendages) on abdominal segments 3 to 6 and also showing the rear end proleg. Credit: Integrated Pest Management for Citrus, 3rd ed. University of California ANR 3303.