AUDITORY SENSE OF HONEY-BEE 195 



not think so, because the trachea does not come in contact with 

 the organ and is no more expanded here than in other places 

 in the tibia. 



So far no external device or apparatus connecting with the 

 internal organ has been found, although Schon imagined that he 

 had found the external portion when he thought he saw two rows 

 of sense cones (Sinneskegel) on the proximal end of each tibia. 

 In position and number these cones correspond exactly to the 

 olfactory pores described by the present writer. When observed 

 without the cylindrical tibia being properly rotated, they often 

 externally resemble cones; but when the tibia is rotated shghtly, 

 so that they lie on the median line of the tibia, the optical illusion 

 becomes evident. Schon found that both the chordotonal organ 

 and these imaginary cones are innervated by the subgenual 

 nerve, and consequently he beheves that the cones act as the 

 external apparatus of the organ. Schon describes and illustrates 

 the internal anatomy of his sense cones (the present writer's 

 olfactory pores), but here does not recognize them as cones, for 

 he follows vom Rath by calling them membrane canals (Mem- 

 brankanale). 



Nothing can be said about the probable function of the chordo- 

 tonal organ, but if it were connected with an external apparatus, 

 similar to that found in some Orthoptera, it might serve as an 

 auditory organ. 



Schon says that there is a great similarity between this organ 

 in Hymenoptera and that in Orthoptera. These organs in 

 bumble-bees, wasps, and Terebrantidae vary greatly with those 

 in ants and honey-bees. In all the organ is fastened to the hy- 

 podermis and in all he found the sense cones and spindle-shaped 

 sense cells which with the subgenual nerve protrude into the 

 nervous ends of the enveloping cells. 



e. Structure of tibial ganglion cells. In the first longitudinal 

 sections made, the writer observed a group of supposedly sense 

 cells which he thought was associated with the chordotonal organ, 

 but after studying more sections it was ascertained that these 

 cells are totally independent of the chordotonal organ, because 

 the former (fig. 14, G) are located at the distal end of the tibia 



