July, 1846. 83 



The Nervous system. The cerebrum (Fig. 17, a.) placed above the oeso- 

 phagus, in form is like two pyriform bodies placed side by side, with the 

 apices anterior and divergent to the base of the antennae. From the most 

 anterior part of each lateral mass passes off the antennal nerve, (Fig. 17 b.) 

 and from the external side, just posterior to the latter, the optic nerve, (Fig. 

 17, c.) From the base of the optic nerve and the cerebrum immediately pos- 

 terior proceed two small branches, which unite to form a single cord, the 

 analogue of the sympathetic nerve (Fig. 17, d.) which passes backwards along 

 the side of the oesophageal crop, to which, after dividing into two principal 

 branches, it is ultimately distributed by numerous minute twigs. Antero-in- 

 feriorly the cerebrum sends off two branches which pass forwards, unite, and 

 form the frontal ganglion (Fig. 17, e.) from which proceeds backwards, be- 

 neath the cerebrum, a single cord running along the upper surface of the oeso- 

 phageal crop nearly to its termination. These two latter branches, the frontal 

 ganglion, and the single resulting cord, constitutes the nervus recurrens, or 

 nervus vagus, (Fig. 17, f.) The nervus vagus, after passing the cerebrum, 

 forms a small swelling, which gives off minute ramuscles to the salivary 

 glands and neighboring part of the oesophageal crop. It also forms a gang- 

 lion (Fig. 17, g.) of moderate size upon the lower part of the oesophageal 

 crop, from which proceed six principal nerves to be distributed to the oeso- 

 phageal crop and stomach. 



The ventral cord consists of a chain of eleven ganglia, connected in their 

 length by a double commissure. 



The first of this chain, the cerebellum, (Fig. 17, i.) is a cordiform gang- 

 lion situated beneath the commencement of the oesophagus, and connected 

 to the cerebrum by its appropriate commissures, gives off the mandibulary, 

 maxillary, and labial nerves. 



The three following ganglia are the thoracic ganglia, (Fig. 18, a.) the 

 first of which is simple, the two others double. These give off nerves both 

 to the extremities and to the neighboring parts. 



The seven remaining ganglia are the abdominal. (Fig. 18, b.) They are 

 all single and give off numerous minute ramuscles in their vicinity. 



Explanations of the figures. 



Fig. 1. Fart of one of the antenna* of spectrum femoratum, highly magnified. 



Fig. 2. Tarsus of do., magnified. 



Fig. 3. The labium, magnified; a, the labial palpi. 



Fig. 4. The tongue, magnified. 



Fig. 5. The right maxilla and palpus, (a,) magnified. 



Fig. 6. The right mandibula, magnified. 



Fig. 7. The labrum, magnified. 



Fig. 8. The intestinal canal, &c, of the female, the size of nature ; a, oeso- 

 phageal crop; b, stomach; c, duodenum ; e, ileum , f, rectum; g, salivary 

 glands ; h, biliary vessels ; i, ovaries ; j, oviducts ; k, an ovum in its pas- 

 sage down the oviduct ; 1, inferior ganglion of the nervus vagus. 



Fig. 9. The inferior portion of the oesophageal crop and stomach laid open. 



Fig. 10. Shows the connection of the commencement of the biliary vessels 

 with the duodenum. 



Fig. 11. Biliary vessels and place of opening into the duodenum. 



Fig. 12. Portion of a biliary tube, highly magnified. 



