328 



INSECTA. 



united to each other by double cords of communication ; but they vary 

 much in number and relative magnitude in different families. Those 

 situated in the thorax are usually of the greatest proportionate size, 

 inasmuch as they furnish the nerves that supply the muscles of the 



Fig. 164. 



Anatomy of Melog: a, the stomach; 6, hepatic vessels; c, intestine; d d, ovaria; e t section of 

 ovary showing the internal cavity;/, vagina; g, spermatheca; h, i, gluten-secretors : 1, supra- 

 oasophageal ganglion of the nervous system; 2,3,4,5, 6,7, 8, ventral ganglia; 99, nervus vagus; 

 10, cephalic nerves ; 11, optic ganglion. 



wings and legs ; the succeeding ganglia give branches to the abdominal 

 segments ; and the last, which is commonly of considerable bulk, sup- 

 plies the sexual organs and the extremity of the colon. 



(858.) It is the general opinion of modern physiologists, that the 



