Central nervous system (CNS):

a. Brain:

• It is the dorsal ganglionic centre of the head supported by the tentorium. It is formed by the union of the ganglia of first 3 segments of the head. Brain is divided into protocerebrum, deutocerebrum and tritocerebrum.

I. Protocerebrum: Formed by the union of the ganglia of pre-antennary segment and gives nerve connection to the compound eyes and ocelli.

II. Deutocerebrum: It is formed from the ganglia of antennary segment and innervates antenna.

III. Tritocerebrum: It is formed by the union of ganglia of third / intercalary segment and are attached anteriorly to deutocerebrum and posteriorly to suboesophageal ganglion.

b. Sub-oesophageal ganglion:

• It is the ventral ganglionic centre of the head formed by the union of ganglia of the gnathocephalic segments.
• It gives nerves to mandibular, maxillary, labial segment, labrum, salivary ducts, and part of cervical muscles in the neck region and corpora allata.

c. Ventral nerve card (VNC):

• Contains chain of segmented ganglia connected by means of longitudinal connectives and transverse commissures.
• Thorax has 3 ganglia (Aggregrated neurons) and abdomen has 8 gangila.
• Thorax Ganglia has nerve connections for legs, wings and general muscles.
• Abdominal ganglia gives off nerves to the muscles of its segment.