80 ON THE ANATOMY OP THE PLY. 



oesophagus, where it emerges from the cephalic nerve centre. 

 Near the posterior extremity of the pharynx, each gives 

 off a branch, and these uniting, bear a small ganglion between 

 them, which I shall name the pharyngeal ganglion. Although 

 I believe it may possibly correspond to the frontal ganglion of 

 Lyonet, as I am not sure, it seems better to name it after 

 the organ against which it is situated. The remainder of the 

 cesophageal nerves is distributed to the muscles of the pharynx. 



A pair of small nerves arise from the pharyngeal ganglion, 

 and run beneath the muscles of the salivary valve, which they 

 supply ; a little anterior to the valve they again unite, and 

 bear a ganglion, which sends filaments to the mouth, I shall 

 call it the oral ganglion. 



The great nerves to the proboscis arise from beneath the 

 central portion of the cephalic nerve centre. Near the posterior 

 part of the first joint of the proboscis they divide into three 

 large trunks, which supply the palpi, the muscles of the pro- 

 boscis, except those of the pharynx, and the great lobes of the 

 proboscis, ending in loops upon the hair bulbs, and supplying 

 the nipple-shaped processes upon the surface of the lobes. 



The nerves to the antennaa, ocelli, and great eyes, will be 

 described with those organs. 



The thoracic nerve centre is supported by the meso-sternal 

 ento-thorax, and consists of four pairs of large ganglia, of 

 which the second are the largest, and the fourth the smallest. 



Externally, the thoracic nerve centre appears to consist 

 chiefly of nerve fibres, having a longitudinal direction. These 

 form a kind of envelope around the several ganglia, which they 

 connect with each other. The ganglia consist chiefly of serve 

 cells, and are largely supplied with tracheal vessels. 



