The larva of any geometrid moth. It progresses forward by first bringing the rear end of the body forward, forming a loop, then moving the front part of the body; called also measuring worm, measuringworm, spanner, and looper. See Geometrid.

the caterpillar of geometrids which has only one pair of midabdominal prolegs.

small hairless caterpillar having legs on only its front and rear segments; mostly larvae of moths of the family Geometridae