1NSECTA. 



957 



which we regard as connected with the 

 c:irni!;itciry system, as we shall hen-alter show. 



As nirivs /' organic Jiatctien, we have now 

 to consider those winch :in: especially given to 

 the different internal organs, and not to the 

 voluntary muscles. Having already considered 

 the transverse nerves, which are distributed so 



especially to the respiratory organs, as rimes of 

 mixed character, those which we regard more 

 especially under the alwve designation arc the 

 si/iHjMithetic ami the ragia or visceral nerves. 

 The sympathetic, or anterior lateral /;iiai;liu 

 (fig. 415, C), are situated two on each side of 

 the oesophagus behind the brain, and anterior 



Fig. 415. 



Aram and nervet of the head andfint legman of a pupa of Sphinx liytutri. 



A, brain; B, optic nerves; C, anterior lateral or lympathetir ganglia; D, intcnnal 

 nerves ; E, froutal ganglion of the recurrent or vagus nerve. ( Nfvport, Phil. Tram. ) 



to the great muscles of the oesophagus and pha- 

 rynx. They are of considerable size, being 

 each about one-third as large as one-half of the 

 cerebrum, and they are connected with most of 

 the other nerves in the head. Thus, besides 

 their connexions () with the brain, one nerve 

 forwards beneath the optic nerves, and 

 joins with a minute filament from the nerve to 

 the antenna', (g,) and also with one to the 

 mandibles, while another passing across the 

 oesophagus is united with the main trunk of the 

 visceral or vagus nerve (e), as it passes along 

 to the stomach, and another branch joins with 

 the tirst set of transverse nerves (A), while other 

 filaments passing outwards are distributed to 

 the muscles of the oesophagus and pharynx. 

 This latter fact, which we have most distinctly 



ined iii Mcliir cicatricosui, a large species 



well adapted both for an examination of this 



and i>l the visceral nerve, is particularly inte- 



from the circumstance that, alter the 



most careful examination, we could not find 



ilier nerve given to those muscles (Jig. 

 4 1 6, C). We have observed a similar distri- 

 Imtioii to the muscles of the oesophagus in Lu- 

 caniis, and also in the Sphinx, so that from their 

 connexions we may justly conclude these gan- 

 glia to constitute at least a portion of the true 

 sympathetic system. From their relative situ- 

 ation they appear to be analogous to the supe- 

 rior cervical itaiii;lia of the sympathetic in \ er- 

 tebrata. It is however, an interesting fact, as 



noticed by Burmeister,* that these ganglia ap- 

 pear to be largest in some of those insects in 

 which the recurrent nerve which we have de-* 

 scribed as the vagus is least developed. Tims, 

 as shown by Muller, Brandt, and Itnrmeisier, 

 these ganglia of the sympathetic system have 

 a large size in the Orthoptera. and, instead of 

 being traceable scarcely beyond the region of 

 the head, send off one or two branches which 

 run along the sides of the oesophagus to a great 

 distance, while the recurrent or vagus nerve, 

 after uniting with these ganglia behind the 

 brain, appears to terminate or be lost in the 

 nerves that originate from them. In Gryllut 

 migratorius, Burmcister has shownf that after 

 the recurrent nerve has formed a minute gan- 

 glion just behind the brain, and united with 

 the first of these sympathetic ganglia, it ap- 

 pears to terminate, while the same ganglion 

 sends off posteriorly two branches, which ran 

 along the upper surface of the oesophagus, where 

 the external one forms a small ganglion, and 

 that the second, or most external of these ante- 

 rior lateral ganglia, also sends a large nerve 

 backwards, at the side of the oesophagus, as far 

 as the crop, where it forms a ganglion and 

 sends off nerves, and at the hinder part of the 

 crop a second ganglion, from which nerves are 

 given to the coecal appendages of the alimcit- 



Op. cit. p. 288. 

 t Id. pi. xxxi. tig. 6. 



