MR. NEWPORT ON THE NERVOUS SYSTEM OF THE SPHINX LIGUSTRI. 411 



lated classes. The motor tract, as we should naturally expect would be the case, is 

 equal in size to the sensitive, the power of motion being evidently the primary en- 

 dowment of organized beings, and existing where sensation can hardly be expected 

 to be found, and where there is only the simplest form of the nervous tissue, entirely 

 without ganglia. 



If the nerves and cords be examined immediately after removal from the body of 

 3n insect, they exhibit a fibrous appearance ; but if macerated a few hours in water, 

 they then look as if formed of series of globules, or rather of disintegrated, irregular 

 parts, as remarked by Dr. Hodgkin in the nerves of the higher animals. It is very 

 certain that the large fibres exchange or interweave a few filaments with each other, 

 to constitute the two tracts of the cord ; and this is also the structure of the nerves 

 in general. It is by approximation of several fibres that the large nervous trunks 

 are formed during the development of the Sphinx ; the transverse nerves unite first 

 with those from the motor root which comes from the cord, and next with those 

 from the ganglion. This union begins, first by a shortening of the nervous columns 

 in a longitudinal direction ; and this is followed by the transverse nerves, and motor 

 root to the Aving, becoming greatly thickened, and gradually approximated from the 

 distal extremity inwards to the middle line of the body. This approximation con- 

 tinues until these are united in like manner with the nerve from the ganglion, so that 

 the development of the nerves to the wings takes place from the periphery to the 

 centre, exactly the same as in the lateral development of the cords, as observed by 

 M. AuDouiN and Dr. Milne Edwards in the smaller Crustacea, The nerves to the 

 wings are thus formed of three series of fibres, which are traceable as distinct tracts 

 along a great part of the whole nerve ; although closely approximated nerves do not 

 coalesce, but only interchange filaments. The nerves of other Articulata exhibit the 

 same appearance as those of insects. The fibrous texture is best seen, and is very 

 distinct, in some of the Crustacea. In the Sphinx, and other insects, after coagu- 

 lation in alcohol, the nerves are contracted in diameter. 



h. . The terminations of nerves are very difiicult to distinguish. They appear to end 

 in, and unite with, the tissues unto which they are distributed. In the Wild Bee 

 I have traced some of the extremities of nerves from the last ganglion, apparently 

 into the very substance of the exterior, or hard covering of the segments of the abdo- 

 men. In the larva of the Blood Beetle, Chrysomela tenebricosa, Linn., I have traced 

 some of the filaments , from nerves of the third ganglion into the cellular texture of 

 the vesicles, or bags, which inclose masses of adipose matter ; but I could not dis- 

 cover that any of the filaments entered the fatty masses. They appeared to terminate 

 in the texture of the vesicles. I have found them distributed likewise over the tra- 

 cheal vessels, and once succeeded in tracing some filaments from a large nerve on the 

 internal side of the posterior thighs of Gryllus viridissimus, Linn., to the cliief tracheal 

 vessel along which it runs. The filaments were expanded over the vessel until they 

 appeared lost in its texture. The same is the case with some filaments from the 

 transverse or respiratory system in the Sphinx and ia Cossus Ligniperda, Steph. The 



