Butterflies have a brain, called the cerebral ganglion which connects to the nerve cord that runs throughout the body. Butterflies also have well developed eyes and other sensory organs like antennae. The antennae are richly covered with sensory organs known as sensillae. The communication between sensory organs, the nerve cord, and brain is necessary for the butterfly to gather and interpret information. Then, it acts upon the information by reacting accordingly to the situation.