196 N. E. McINDOO 



and the latter (0) at the proximal end of the tibia, and no con- 

 nection could be found between them, except that the same 

 nerve {N) sends off a branch to each group of cells. 



For lack of a more appropriate name, the cells under discussion 

 may be called tibial ganghon cells, although the writer knows of 

 no similar group in insects. Schon apparently did not see them 

 and perhaps this is the first time for them to be described. They 

 lie in a mass (fig. 17, G) between two tracheae (Tr) at the 

 extreme distal end of the tibia. The distal end of the group is 

 attached to the hypodermis near the articulation, while the 

 proximal end terminates in a branch of the main nerve. 



Figure 18 is a cross-section showing this group of cells (G) 

 just departing from the nerve {N), and some of the fibers may be 

 seen between the two tracheae {Tr) running to the hypodermis. 



This group of cells is slightly larger than the chordotonal organ, 

 but the individual cells (figs. 25 and 26) in it are practically the 

 same in shape and size. as are the sense cells in the chordotonal 

 organ. 



SUMMARY 



Bee-keepers are agreed that bees can hear, yet they cannot prove 

 it, and critics still contend that it has never been experimentally 

 proved that any insect can hear; nevertheless, within the last 

 few years some good experimental results have been obtained. 



The special sound-producing apparatus of the honey-bee con- 

 sists of the membranes lying between the axillaries at the bases 

 of the front wings. Muscles, lying in the thorax and attached 

 to these axillaries, contract and relax very quickly, thereby 

 causing the axillaries to vibrate; consequently, the above mem- 

 branes are caused to vibrate rapidly, thus producing the piping, 

 teeting, or squeahng noise commonly heard when a bee is 

 squeezed. 



Up to date five so-called auditory organs have been found in 

 the honey-bee. Judging from their anatomy, the pore plates, 

 Forel flasks, pit pegs, and Johnston's organ, all located in the 

 antennae, do not seem to be well fitted to act as sound receptors; 

 but the chordotonal organs, lying in the tibiae might be better 



