Supraesophageal ganglion
The supraesophageal ganglion (arthropod or fish brain) is the first part of the insect and fish central nervous system. It receives and processes information from the first, second, and third metameres. The supraesophageal ganglion lies dorsal to the esophagus and consists of three parts: the protocerebrum (with eyes), the deutocerebrum (with antennae in insect), and the tritocerebrum. The lobes of the tritocerebrum split to circumvent the esophagus and begin the subesophageal ganglion.
Supraesophageal ganglion(5), Subesophageal ganglion(31)
The subesophageal ganglion continues the nervous system and lies ventral to the esophagus. Finally, the segmental ganglia are found in each body segment as a fused ganglion and they provide the segments with some autonomous control.