MR. NEWPORT ON THE NERVOUS SYSTEM OF THE SPHINX LIGUSTRI. 391 



deposit of gelatinous pink-coloured matter, precisely in the situation of the red bands 

 which encircle the body of the perfect insect ; but no distinct traces of organization, 

 in the form of scales, can be detected in it, nor have the black bands as yet begun 

 to make their appearance. The nervous system is now about to undergo its final 

 change. There is an evident alteration in the appearance of the ganglia, although 

 they retain the same situation, both in the thorax and abdomen, as in the month of 

 April. The second ganglion is much decreased in size, has become of an oval form, 

 and is not very distinct from the cords themselves. The third, fourth, and fifth gan- 

 glia are approaching nearer together, and are tending to form the two portions of 

 the large thoracic mass which exists in the perfect insect, [Plate XIII. fig. 6.] and 

 from which the nerves to the legs and wings are distributed. But the sixth gan- 

 glion still lies upon the division between the thorax and abdomen, and its nerves 

 are still disposed in an irregular manner, in consequence of the change that has 

 taken place in the direction of the muscles of the segment to which they are distri- 

 buted. The other ganglia remain in the same segments of the abdomen as in the 

 previous stages of development. The transverse series of nerves [fig. 1, 2. {e,h, o, o), 

 fig. 6. (o, p)] have a little shifted their position, and instead of remaining, as in 

 the larva, almost closely attached to the anterior part of the abdominal ganglia, 

 they have moved forwards, and lie nearly equally distant between them ; have 

 become more uniform in size through their whole length ; and have lost the gan- 

 glionic appearance they exhibited during the earlier stages of the pupa state. The 

 cerebral ganglia continue very distinct from each other, while the optic nerves, 

 which proceed from them laterally, are extending in every direction, and are nearly 

 as large as the ganglia from which they are developed. The enlargement has taken 

 place chiefly upon the anterior surface, outwards, forwards, and downwards ; but 

 these parts of the nervous system are still very far from being completed. The patch 

 of gelatinous dark-coloured substance which is seen upon the base of the optic 

 nerves, close to the cerebral ganglia, immediately after the Sphinx has entered its 

 pupa state, although up to the present period it has not been increased or extended, 

 has now assumed a distinctly organized appearance, its outlines being clearly de- 

 fined. Its outer margin is smooth, and continuous with an exceedingly delicate 

 transparent membrane covering the whole surface of the nerve. The interior mar- 

 gin is more distinct, and is corrugated and folded upon itself so as to resemble a 

 partially closed sphincter. It is now removed a little further from the cerebral gan- 

 glia, preparatory to its subsequent expansion over the extremity of the visual organ, 

 of which it seems destined to constitute the choroid. It exhibits exactly the same 

 appearance during the development of Papilio Urticce, Linn., [Plate XV. fig. 31. (c)] 

 in which I have watched it even more attentively than in the Sphinx. 



It is at this period of development that we are enabled to trace with the greatest pre- 

 cision the distribution of the vagus nerve [Plate XIII. fig. 3. (e. e)] to the oesophagus 

 (/, h) and dorsal vessel Qi, h), and its connexions with the anterior lateral ganglia 



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