196 N. E. McINDOO 
and the latter (O) at the proximal end of the tibia, and no con- 
nection could be found between them, except that the same 
nerve (NV) sends off a branch to each group of cells. 
For lack of a more appropriate name, the cells under discussion 
may be called tibial ganglion cells, although the writer knows of 
no similar group in insects. Sch6én apparently did not see them 
and perhaps this is the first time for them to be described. They 
lie in a mass (fig. 17, @) 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 (V), and some of the fibers may be 
seen between the two tracheae (7'r) running to the hypodermis. 
This group of cells is shghtly 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 squealing 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 
