62 
CHAPTER X. 
NERVOUS SYSTEM. 
Ganglionic Chain — Brain^ or Supra-oesophageal Ganglion — 
Nerve Fibrils — Gangliofiic Cells — Regulation of Animal Life 
— Co7U7Jiis sural Fibres — Refex Actio7i — Ga7iglia connected 
with IVrngs a7td Legs — Number of Ga7iglia — Muscles sup- 
plied with Nc7'ves — Vegetable Life of l7isects. 
The nervous system has occupied the attention of 
many naturalists, amongst whom may be specially 
mentioned Swammerdam (158), Dufour (32), New- 
port (117), Blanchard (5), Dujardin (33), Brandt 
(10), and Biitschli (i8). In the bee the nervous 
system consists of a series of enlargements called 
ganglia, or a collection of nerves united by interven- 
ing longitudinal double cords. This ganglionic chain 
extends from the tail end of the body beneath 
the stomach (frontispiece, ^), up the middle line of 
the oesophagus, which it encircles, and reunites above 
it in the head {a). The ganglia are placed in order, 
one in front of the other, and are also double. 
The largest is in the head, and is called the brain 
( Fig. 29, a), or supra-oesophageal ganglion. The 
one under the oesophagus (/) is called the sub- 
oesophageal ; whilst the nerve fibres (g) which en- 
circle the oesophagus and connect the two, are called 
the oesophageal collar. The others are termed 
ganglions, or medullary centres. Bundles of nerve 
fibres enclosed in a sheath (Fig. 30, b), form the 
