AUDITORY SENSE OF HONEY-BEE 189 
probably be more correct by classifying them as tactile organs 
rather than as auditory perceptors. 
c. Structure of other antennal organs. Relative to the other 
antennal organs, there are four, all of which are really hairs. 
The tactile hairs (fig. 13, 7 Hr) or sensilla trichodea are scarce 
on the antennae of the male honey-bees, but numerous on the 
antennae of the females. They are regarded by all the observers 
as tactile organs. ‘The pegs (Pg) or sensilla basiconica are absent 
in the males, but numerous on the antennae of the females. They 
are generally considered as olfactory organs, because their tips 
are covered with very thin chitin. The present writer believes 
that they are very delicate touch organs. 
The pit pegs (fig. 138,-PP) or sensilla coeloconica and Forel 
flasks (FJ) or sensilla ampullacea are hairs inside of pits. On the 
antennae of the males both of these types are somewhat numer- 
ous, but on the antennae of the females they are comparatively 
scarce. Viewed superficially, one type cannot be distinguished 
from the other, but sections show that the pit pegs are usually 
the larger in diameter. Relative to the antennae of workers, 
most of these organs (fig. 3, PP and Fl) lie in groups on the 
sixth to twelfth segments, and counting both types combined 
there are not more than 100 individual organs on each antenna. 
In regard to their internal structure, they differ somewhat, as 
may be seen by referring to figures 10, 11, and 13. In both types 
the semitransparent hair (Hr) ends in a cavity (Ca), which com- 
municates with the exterior by a minute aperture (Ap), and each 
hair is connected with a nerve strand (St), which runs to a sense 
cell group (SCG). The function of these organs is usually 
regarded as problematical, but still a few authors have called 
them auditory organs. The present writer has no conception 
of what their function is, but for some time he has looked upon 
them as more or less degenerated structures. 
At this place the writer wishes to call attention to an erroneous 
idea which text-book writers still persist in handing down. Be- 
fore understanding the internal anatomy of antennae, some of the 
early microscopists imagined that they saw gland cells among the 
masses of sense-cell groups. This led to the idea that in order 
