AUDITORY SENSE OF HONEY-BEE 175 
SO-CALLED VOCAL ORGANS OF INSECTS 
In the higher animals the vocal organs are located in the throat, 
but in insects we should not expect to find their vocal organs 
in the buccal cavity, because this class of animals has a totally 
different organization. Hence, we must look elsewhere for the 
vocal organs of insects. 
1. Sound-producing organ of honey-bee 
In 1911, while determining that bees have an olfactory sense, 
the writer also ascertained that they have a means of making a 
piping or squealing noise. 
a. Experiments to determine how bees make sounds. Hundreds 
of worker bees with wings pulled off or cut.off were tested, and 
from mere observations it appeared that the squealing noise was 
made by the thorax. To be sure that the noise was made by the 
thorax, the abdomens of several bees were cut off. These mu- 
tilated bees could walk fairly well and when irritated made the 
squealing noise. Several other bees with both heads and ab- 
domens cut off were likewise tested; these were so badly mutilated 
that in only one case did a thorax make the noise. Bees with 
wings cut off, when observed under a binocular, further confirmed 
the view that the squealing noise is made solely by the thorax, 
because the bases of the wings were seen to vibrate rapidly. 
In 1920 the preceding line of experimentation was continued, 
and the following results were obtained. The loud buzzing of 
bees is made by the distal portions of both pairs of wings, while 
the squealing noise is made only by the bases of the front wings. 
When worker bees or drones were squeezed, or when their wings 
were held firmly, or were cut off or pulled off, these insects usually 
made the squealing noise. When no noise was heard, the insect 
being tested was placed on a large inverted pan lying on a table. 
The pan thus serving as a resonator usually intensified the feeble 
noise so that the human ear could hear it. Bees with the wing 
stubs glued did not make the noise, but after dissolving off the 
glue the insects made the noise as usual. When the muscles 
attached to the roots or axillaries of the wings were cut, the 
