What is a "feeler"?

A feeler is a pair of segmented sensory appendages that emerge from the insect's head. They are also known as antennae and serve a variety of functions such as sensing their environment, detecting food and pheromones, and communicating with others of their species. Feeler length, shape, and structure vary greatly between different insect species, and they can be used to help distinguish between different groups of insects.