J78 ANATOMY AND PHYSIOLOGY 



of the Coleoptera destitute of abdominal ganglia ; 1, 1 

 lobes of the anterior or cerebral ganglion ; a, a, optic 

 nerves; b y b, eyes: 2, posterior cephalic ganglion; 

 3, prothoracic ganglion, emitting two pair of nerves 

 on each side, 3'; 4, mesothoracic ganglion, sending ofl 

 two pair of nerves, one, 4', for the wings, the other 

 4'', for the middle legs ; 5, metathoracic ganglion fur- 

 nishing four pair of nerves, the anterior, 5', for the 

 hinder legs, the others, 5", for the first segments of the 

 abdomen ; 6, ganglion representing the ordinary abdo- 

 minal series ; besides the two medullary cords, 6' 6', 

 which run in a straight line to the extremity of the 

 body, it sends out on each side five pair, 6", distributed 

 among the fourth, fifth, sixth, seventh, and eighth 

 abdominal segments; d, d, mandibular nerves; e, e 

 nerves of the antennae. 



Fig. 2, nervous system of the caterpillar of Sphinx 

 Ligustri, a few days before becoming a chrysalis. 

 1, cerebral ganglion, 2, posterior do., 3, 4, 5, 6, 

 thoracic ganglia, 1, 8, 9, 10, 11, 12, abdominal 

 ganglia, 0, o, o, system of transverse nerves, more 

 distinctly seen in fig. 3, in which 3, 4, 5, represent 

 the three thoracic ganglia, a, a, central nervous filet, 

 b, by b, b, nerves furnished by this filet, c, c, c, c, ner- 

 vous threads separating from the preceding nerves 

 and which, by uniting when they reach the ganglion 

 constitute the central thread. 



Fig. 4 is a delineation of the nervous system in 

 the chrysalis of Sphinx Ligustri, thirty days after its 

 change, showing the much greater state of concen- 

 tration it has already attained. The posterior thor- 





