Page:Jardine Naturalist's library Entomology.djvu/184

178 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 cephalic ganglion; 3, prothoracic ganglion, emitting two pair of nerves on each side, 3′; 4, mesothoracic ganglion, sending off two pair of nerves, one, 4′, for the wings, the other, 4′′, for the middle legs; 5, metathoracic ganglion furnishing 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 abdominal 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 antennæ.

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, 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, b, b, b, nerves furnished by this filet, c, c, c, c, nervous 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 concentration it has already attained. The posterior