414 MR. NEWPORT ON THE NERVOUS SYSTEM OF THE SPHINX LIGUSTRI; 



Immediately after the insect has assumed the pupa state [Plate XV. fig. 22.], all the 

 ganglia are brought closer together, and the cords are disposed more irregularly than 

 at any other period, in consequence of the shortening which has taken place in every 

 segment of the body, by which the cords have been rendered too long to lie in a 

 direct line. Those cords which connect the first five ganglia are somewhat increased 

 in size. It is at this period there is the greatest activity, and sometimes irregularity in 

 the progress of the changes. The fourth and fifth ganglia, and their intervening cords 

 (which are those parts in which the first great changes commence), are often nearer 

 together and have more coalesced at this period in some specimens, than in others 

 at five or six hours later. This coincides with what occurs in the Sphinx ligustri, in 

 which the precise period when the coalescence of ganglia takes place cannot posi- 

 tively be stated, since it varies a little in different specimens, and depends probably 

 upon the temperature of the atmosphere, and upon the vigour of the insect at the 

 time of changing, 



One hour after transformation [Plate XV. fig. 23.], the cerebral ganglia have become 

 more closely united, the nerves to the antennae more distinct, and the rudiments of 

 the optic nerves more developed at their base. The fourth and fifth ganglia are 

 still approaching each other, and the cords are larger in diameter at their connexion 

 with the fifth, the anterior part of which has become less distinct, and seems about 

 to coalesce with them. The distance between the remaining ganglia is still decreasing, 

 and the investing membranes, or exterior surface of the cords, exhibit a corrugated 

 appearance, as if in the act of becoming shortened. In the Sphinx ligustri, besides 

 the longitudinal cords and ganglia, and nerves given directly from them, we have 

 seen there are others lying upon them, — the transverse or superadded nerves. There 

 are like series in Papilio urticce, L., the distributions of which are nearly similar. The 

 first series begins immediately behind the first suboesophageal ganglion (6), where 

 the nerves run directly outwards, along the course of the trachea, which are distri- 

 buted over the first ganglion, and come directly from the first spiracle. Some of the 

 branches unite with nerves from the second ganglion {d), while the main branch of 

 this segment runs in the course of the muscles at the back part of the head. Behind 

 the second ganglion, branches unite with the large nerve which comes from the cord 

 between the second and third ganglion to supply the first pair of wings {f), and which 

 is apparently single, and does not originate, as in the Sphinx, one root from the cord 

 and the other from a ganglion. Behind the third ganglion, the nerve from the cord 

 to the second pair of wings (?) receives a branch from the third series (A), while the 

 greater number of the nerves pass outwards to the muscles. A series of these trans- 

 verse nerves exists, as in the Sphinx, just anterior to each of the remaining ganglia 

 (o, o, o), unto the nerves of which they give a few filaments, while their main branches 

 are distributed separately among the tracheae and muscles, excepting only those of 

 the fourth, fifth, and sixth series, which become approximated to the nerves from the 

 corresponding ganglia, and in the development of the Butterfly at this period, afford 



