THE CANADIAN ENTOMOLOGIST 31 



passing far beyond all others of their kin in the degree of fusion of the con- 

 nectives in the larval nervous chain. 



Further Details of a Few Dissections. 



The nervous system was examined in a series of caterpillars representing 

 all the families available at the time. A brief outline of a few examinations 

 will be sufficient for the present purpose. 



Papilio polyxenes Fabr. 

 Plate II, Figs. 1 and 2. 



The condition shown in the figures appeared to be general in the butter- 

 flies. The thoracic connectives are widely separated throughout with the 

 oblique muscles passing between them in the 2nd and 3rd thoracic segments, 

 with a lateral nerve from the connectives of all three thoracic segments. The 

 abdominal connectives are separated for a considerable distance in front of 

 each ganglion and their double origin is indicated on the remaining part by a 

 strongly impressed median line. There are seven abdominal ganglia, with the 

 last longer than wide, but not constricted, indicating its double origin only by 

 the number of nerves to which it gives rise. 



Ceratomia amyntor Hbn. 

 Plate II, Figs. 5 and 6. 



The infraoesophageal ganglion is thick and shows traces of an impressed 

 median line. The connectives between that and the 1st thoracic ganglion are 

 longer than in Sthenopis thiile and distinctly separated, though adjacent. Be- 

 tween the 1st and 2nd thoracic ganglia the connectives are widely separated, 

 except for a short distance behind the first ganglion, where they are adjacent. 

 They are distinctly separated at their insertion into the 2nd ganglion. The 

 connectives between the 2nd and 3rd thoracic ganglia are as those between 

 the 1st and 2nd. Those between the succeeding ganglia are adjacent, but 

 distinctly separated. This is a condition far removed from that in S. thiile 

 with an almost solid ventral cord. 



Distinct nerves from the connectives are found between the 1st and 2nd and 

 the 2nd and 3rd thoracic ganglia, but not elsewhere. They are connected with the 

 transverse branches of the median nerves and with the first pair of nerves from 

 the ganglia. The development of the median system is indicated sufficiently 

 for the present purpose in the figure; as usual, it is most highly developed in 

 the thorax. The last ganglion, the 7th abdominal, is elongate and evidently 

 constricted. 



Sphinx kalmia S. and A. 



The venfral cord is similar to that figured for Ceratomia, except that the 

 connectives are adjacent in the thoracic segments for almost the cephalic half 

 of their length, and the abdominal connectives are much more completely fused, 

 though still showing a median line. The median and connective nerves of the 

 3rd thoracic segment are complex, as in Ceratomia. The last ganglion is evi- 

 dently complex, with a distinct constriction. 



Sphinx drupiferarum S. and A. 



The connectives are more slender in the abdomen than in Ceratomia, but 

 still showing everywhere the median line which indicates their double origin. 

 Those of the 1st abdominal segment are about three times the length of the 



