EXPLANATION OF ANATOMICAL PLATES. 27 



Fig. 3 h cxhibita the tennination of the intestinal canal in the rectum. 



Fig. 5 aa exhibits the salivary apparatus, having fleshy organs at the base of the head, and tubes that 



pour saliva into the mouth during mastication. 

 Fig. 4 aa. General arrangement of the urinary organs, the secreting vessels disposed on the tops of 



small tranches ; cd, the bladder ; h, deferential canal. 

 Fig. 1 represents an arrangement that exists among the bombardiers : a, accessory bladder ; c, principal 



bladder. 

 Fig. 6 exhibits the biliary organs cc, fringed as in the cockchafer. 



III. CIECULATOEY SYSTEM.— PLATE B. 



Fig. 13 : aaa, dorsal vessel ; b, wings; cd, diminution in diameter towards the head. 

 Fig. 14 shows the interior walls of the dorsal vessel, circular fibres, arrangement of its walls, and the 

 * valves. 



IV. RESPIRATORY SYSTEM— PLATE B 

 Fig. 12. Spiracles or stigmata. 



Fig. 9. Another form of stigmata. 



Fig. 16. Stigmata of Dytiscus margenalis^, edges of which are beset with hairs. 



Fig. 15. Stigmata of the cockchafer, where there is a membrane drilled with holes. 



Fig. 8. A circular membrane stretched over the valves, and ornamented with colors. 



Fig. 17 shows the rows of stigmata along the sides. 



Fig. 10 exhibits the system of the trachea or air-vessels : aa, stigmata ; bb, ventral spiracles ; cc, 



trunks closed at their extremities ; ee, bladder-like bag, receiving the longitudinal trachea ; 

 fff, trachea for the wings ; gg & hh, bags for air ; k, trachea for the thorax ; II, trachea 



for the head ; o, base of the tcgmina. 



V. NERVOUS SYSTEM.— PLATES B & E. 

 Fig. 2 ( PI. B), ghilll, exhibits the principal ventral chord, with its ganglia. 



Fig. 2 (PI. E). Nervous chord of the cockchafer : 1 1, lobes of the anterior cephalic ganglion; aa, 

 optic nerves ; hb, eyes ; 2, posterior cephalic ganglion ; 3, prothoracic ganglion ; 4, meso- 

 thoracic ganglion ; 5, mctathoracic ganglion ; 6, ganglion of the abdominal series ; dd, 

 mandibular nerves ; cc, antennae. 



Fig. 1. Nervous system of the caterpillar of the Sphinx ligustri, a few days before it becomes a chry- 

 salis : 1, cerebral g.anglion ; 2, posterior ditto j 3, 4, 5, 6, thoracic ganglia ; 7, 8, 9, 10, 

 11, 12, abdominal ganglia; ooo, system of transverse nerves, more distinct in fig. 3, in 

 which 3 4 5 represent the three thoracic ganglia ; aa, central nervous fillet ; bbbb, nerves 

 fumished»by the fillet ; eeee, nervous threads separating from the preceding nerves, and 

 which, by uniting when they reach the ganglion, constitute the central thread. 



Fig. 3. Nervous system of Sphinx ligustri thirty days after its change, showing a greater condensation 

 of the nervous masses : the posterior thoracic ganglia are now united into one mass. 



