PHYSIOLOGY OF THE BEE. 83 



the separation of their filaments to inclose the gullet 

 together with a more plainly-defined distance be- 

 tween the cords which run parallel through the rest 

 of the body. 



Fig. 24. — Nervous System of Perfect Insect. ^ 



In the perfect insect we observe some decided 

 modifications to have taken place. The head por- 

 tions have grown proportionally larger, and show a 

 loop for the passage of the oesophagus, while two 

 large ganglia in the thorax indicate the seat of im- 

 pressions and impulses connected with the organs of 

 motion — wings and legs — which had no existence in 



G 2 



