48 BEES AND BEE-KEEPING. 



brought near to one side of the body, will imme- 

 diately cause the residue of the insect to retreat in 

 the opposite direction. If the hair-pin be actually 

 put into contact with the body, the legs will at once 

 be set to work to rub from the part the cause of 

 annoyance. Facts like these are well known to 

 physiologists, and those who desire to extend their 

 acquaintance with them are referred to such works 

 as Dr. Carpenter's Manual, or Huxley's Text-book. 



At Fig. 1 1 (C), we have an enlargement of one of these 

 ganglia, which shows it to be really double, one-half 

 belonging to the right, and the other the left, side of 

 the body. Let us suppose the lateral threads (n) (which 

 are turned upwards, for the sake of convenience, in 

 the illustration) to be provided to the right front leg. 

 If this member be pinched, touched, or influenced in 

 any way, an impression travels along the nerve until 

 the ganglion is reached, when the fibres take four 



independent courses, all indicated in the figure 



some run forwards towards the head, others back- 

 wards towards the relatively posterior nerve masses 

 still others to the opposite half of the ganglion, thus 

 uniting in the impression the right and left sides 

 — such are called commissural fibres (cf, Fig. n) • 

 and others, again (rf), after entering the mass of 

 the ganglion, and coming into contact with its 

 cells, return by the same side. The impression pro- 

 duced immediately results in a movement, reflected 

 from the ganglion, without any intervention of the 

 action of the brain, and so such movements are called 

 reflex. The commissural fibres would originate action 

 on the opposite side of the body, while the fibres 



