176 N. E. McINDOO 
squealing noise ceased for all time, and when the thorax of a live 
bee was held gently between the fingers the tingling sensation 
perceived indicated that these muscles vibrate very rapidly, 
setting in motion the axillaries and membranes in the bases of 
the wings. A microscopical examination of all the front wings 
pulled off showed that every bee with wings thus detached was 
able to squeal so long as one or two intact axillaries remained in 
the thorax. 
Besides the buzzing and squealing noises made by bees, the 
writer often heard a crackling sound while observing these insects 
flying around an alighting-board. He could not detect how this 
sound is made, but imagined it produced by the wings striking 
together accidentally. 
All attempts, except one, trying to get bees to respond to the 
squealing of other bees failed. Or at least the bees exhibited no 
reactions which could be attributed as signs of hearing. Never- 
theless, one squealing bee was held in a hidden position a few 
inches from an alighting-board; at once one of the many workers 
on this board seemed to take notice and flew to the screen behind 
which the squealing bee was hidden, and then it came immediately 
to the squealing bee, which it began to examine by running around 
it and smoothing its hair. 
A queen bee, resting on a comb with workers surrounding her, 
when squeezed, squealed and the near-by workers became excited. 
Such experiments really do not mean much, because too many 
interfering factors cannot be eliminated. The original plan of 
the writer was to carry on experiments in which he hoped to 
‘be able to classify and to record on phonograph records the 
various sounds heard in a hive of bees. If this were possible, 
he intended to reproduce these sounds and then to determine 
whether or not bees respond to them. When he was transferred 
from the division of Bee Culture, this line of experimentation was 
discontinued. 
b. Morphology of sound-producing organ. Several live worker 
bees and drones were held under a binocular and the following 
observations were recorded: When a bee is held by the legs it 
buzzes continuously. The wings are held straight out at right 
