AUDITORY SENSE OF HONEY-BEE 191 
of cross-sections it may be seen to arise merely as a nerve 
attached to the hypodermis; then the nerve suddenly runs to a 
few large cells (fig. 15); a few sections further on the nerve dis- 
appears, and the organ assumes a spherical shape (fig. 16, O), 
and the walls are lined with a thick layer of large cells, leaving 
a cavity in the center, which is apparently filled with a liquid 
(probably only blood). 
Figs. 14 to 18 Sections, showing structure of tibial sense organs. Figs. 14 
and 17, each a semidiagrammatic drawing from two consecutive longitudinal 
sections of hind tibia of a drone, showing relative position of tactile hairs (THr), 
olfactory pores (Por), chordotonal organ (QO), and ganglion cells (@), all of which 
are innervated by the same nerve (N, too wide here), although a small branch 
of this nerve, called the subgenual nerve (SN) runs directly to the chordotonal 
organ; fig. 14, X 32, and fig. 17, X 58. Figs. 15, 16, and 18, cross-sections through 
tibia of a worker, showing relative position and shape of chordotonal organ (QO) 
and ganglion cells (@); X 53; fig. 15, through proximal end of group of ganglion 
cells. A, apodeme; B, blood chamber; F, fat cell; Hyp, hypodermis; M, muscle; 
N, two main branches of nerve; 7’r, trachea. 
Using Schén’s terminology, the detailed description of a single 
chordotonal organ is as follows. The tibial nerve after im- 
mediately emerging from the femur is apparently divided into 
two large branches, because in all of the cross-sections made 
two comparatively large nerves (figs. 15, 16, and 18, N) were 
found. A short distance from the femorotibial articulation one 
