Palmerworm, also known as cankerworm or inchworm, is a type of caterpillar that is widely found across the globe. This insect is known for its distinctive way of crawling, which is different from other caterpillars. There are several synonyms for palmerworm, including looper, spanworm, and measuring worm. These names are derived from the way the insect moves, as it arches its body in a looping motion to advance along. In addition to these synonyms, the palmerworm is also sometimes referred to as the fall cankerworm, due to its seasonal cycle of infesting trees during autumn. These different names all refer to the same insect, and are commonly used in different parts of the world.