78 ON THE ANATOMY OP THE PLY. 



ganglia of the proboscis are situated. I shall call these the 

 cssophageal nerves. 



e^ central ganglia form an ovate mass pierced by the 

 oesophagus, and supported below by the expanded extremity 

 and crura of the thoracic nerve trunk. A slight groove above 



DESCRIPTION OF PLATE VII. 



Fig. 1 . The entire ventral cord and the cephalic and thoracic ganglia. 

 The great splachnic ganglion and a few sympathetic nerves are repre- 

 sented as they would appear if it were possible to detach them from the 

 viscera, to show their connection with the moto-sensory nerves, x 15 diam. 



Fig. 2, A vertical section through the middle of the cephalic ganglion, 

 showing the oesophagus, the nerves of the antennas and proboscis at their 

 origin, and a portion of the cephalo-thoracic ventral cord, and the cerebroid 

 ganglion of the right side with its cms : to show the relations of these 

 parts. X 30 diam. 



Fig, 3. The anterior termination of the great cephalo-thoracic ventral 

 cord, showing the crura of the optic ganglia and nerves to the proboscis ; 

 the pharyngeal and oral ganglia are also represented, x 30 diam. 



Fig. 4. The cerebroid ganglia, isolated. X 100 diam. 



Fig. 6. A portion of the interior of the great eyes, showing from 

 above downwards, the following parts : a portion of the compound corm a, 

 the cones and rods, with nuclei imbedded in their inner < xtremities, the 

 common retina, the clear optic nerve, and the optic zone with its tracht al 

 vessels. X 150 diam. 



Fig. 6. Inner extremities of rods with their nuclei ; a plexus of 

 tracheal vessels and the choroid pigment is seen between the rods, x 500 

 diam. 



Fig. 7. A cone detached, with the outer extremity of its rod and a 

 single facet of the cornea, showing the structure of the rod, disposition of 

 pigment, and nuclei in the pigment layer of the cone, x 600 diam. 



Fig. 8. One of the ocelli, showing the cornea, choroid, and plexus of 

 tracheal vessels, x 200 diam. 



Fig. 9. The cornea of one of the ocelli, seen in profile, x 200 diam. 



Fig, 10. Ultimate nerve loops of the sympathetic nerves of the ovary. 

 X 600 diam. 



