178 
ANATOMY AND PHYSIOLQ.GY 
of the Coleoptera destitute of abdominal ganglia ; 1, 1, 
lobes of the anterior or cerebral ganglion ; a, a , optic 
nerves ; b, b, eyes : 2, posterior cepbaHc ganglion ; 
3, prothoracic ganglion, emitting two pair of nerves 
on each side, 3'; 4, meso thoracic ganglion, sending off 
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 ei glith 
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, G, 
thoracic ganglia, 7, 8, 9, 10, 11, 12, abdominal 
ganglia, o , 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 } by 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 tlior- 
