280 THE CANADIAN ENTOMOLOGIST 



Recurrent Nerves. The Frontal Ganglion lifes upon the middle line of the fore- 

 intestine well in front of the brain. It receives on each side the large sympathetic 

 branches of the fronto-labral, called the Arched Nerves, and gives rise 

 to the Cephalic Nerve in front, and to the Recurrent Nerve behind. The 

 Cephalic Nerve passes directly forward along the middle line of the intestine to 

 the base of the clypeus; here it enlarges to form the Cephalic Ganglion which 

 gives two pairs of nerves to the intestine and receives on each side a slender 

 thread, the Minor Arched Nerves, or the second sympathetic branch from the 

 fronto-labral nerve. The frontal nerve bifurcates at the anterior end of the 

 cephalic ganglion and each, branch gives many threads to the muscles of that 

 region. One of these threads is connected through a minute ganglion of the 

 peripheral sympathetic system with a slender branch from the fronto-labral 

 ganglion. 



The Recurrent Nerve passes backward from the frontal ganglion as a slender 

 strand along the median line of the intestine, beneath the heart and brain, and 

 expands into a Caudal or Stomachic Ganglion at the base of the oesophagus. 

 From the caudal ganglion several filaments arise as well as two larger nerves 

 which were traced for a short distance one along each side the mid intestine. 

 Nearly midway between the frontal ganglion and the brain the recurrent nerve 

 expands into an elongate ganglion which gives three pairs of lateral nerves to 

 the fore-intestine. A short distance behind the brain the nerve again enlarges 

 slightly, forming a minute Median or Hypocerebral Ganglion connected by a 

 delicate thread with the second ganglion of the paired lateral group. Along 

 its course the recurrent nerve innervates the fore and midintestine, and certain 

 delicate threads were noticed to enter the wall of the heart. 



The Paired Lateral Section. 



PL X, Figs. 2 and 8; PI. XI, Figs. 1 and 3. 

 The arrangement of this plexus of ganglia and nerves varies considerably 

 in different specimens. Usually there is found a short nerve arising from the 

 side of the caudal part of each half of the brain. This nerve enlarges directly 

 to form a fusiform ganglion, "1", PL X, Fig. 8, which gives rise by short nerves to 

 two others. One of these, "2", fusiform in shape, innervates that part of the 

 intestine immediately behind the brain, sends fibres to the heart, and one to the 

 cephalic ganglion of the median nerve. This ganglion sometimes arises directly 

 from the brain by a separate commissure, but is always closely connected with 

 the first ganglion. The third ganglion, "3", of this lateral sympathetic section is 

 nearly circular, flattened, and connected with the first ganglion l)y two short 

 nerves; it supplies the fan-shaped muscles of the oesophagus and the neighbouring 

 tracheae. What I have called the first ganglion is sometimes but little enlarged 

 and then appears more like a stout nerve, but as a riile there are three distinct 

 ganglia. The first ganglion, besides apparently giving delicate threads to 

 the tracheae with which it is always in close contact, gives off two very interest- 

 ing nerves, the Sensory and the Lateral Nerves., 



The Sensory Ner\e passes from the cephalic face of the ganglion cephalad 

 past the brain, to which it is joined by a short connective, and is continued latero- 

 cephalad in close connection with the optic nerve, which it finally leaves, and 



