"Most Lepidopterae (moths and butterflies) caterpillars have three true legs, four prolegs and an anal clasper (often referred to as a 5th proleg) which they use to walk and to hold on to foliage. However, not all caterpillars have this same distribution of legs. The majority of one large family of moths, the Geometridae, have only one pair of prolegs and a pair of rear claspers which cause them to walk by advancing one end of their body at a time, forming a loop in their folded body. This has given rise to this family of caterpillars being known as âloopersâ." ...... Wildlife Insight

