HEAT PRODUCTION OF HONEYBEES IN WINTER. 5 
DISCUSSION OF THE TEMPERATURE RESPONSES IN THIS 
EXPERIMENT. 
The colony used in the experiment here reported was taken to 
Washington from the suburbs some time prior to the beginning of 
the experiment. The bees were placed in the calorimeter and then 
it was found that the apparatus was defective and it was necessary 
to remove them. During the interval before the experiment here 
recorded was begun, they were placed outside where they were 
free to fly when the weather permitted, and they had several flights 
and carried out the dead bees. They were therefore in good condi- 
tion at the beginning of the experiment. 
For several hours after the hive was again placed in the respira- 
tion chamber, the temperatures of the hive and bees were high, 
chiefly as a result of the disturbance arising from the handling 
necessary at this time. They were put in place at 3 p. m. on Decem- 
ber 11, and during the night the temperature of the bees on one 
occasion, and in one point only, rose to 35° C. During the night 
the temperature of both the chamber and the bees drifted down, 
until shortly after noon on the 12th, when they may be considered 
as having reached normal quiescence. Just when the bees definitely 
formed a winter cluster is not clear from the data, but certainly 
when they had reached quiescence they were clustered. 
In the graphic charts of temperatures of this colony, records are 
included for thermocouples 6, 7, and 12, these being the ones which 
were in the center of the cluster, which was located near the top 
and slightly to one side of the hive. For comparison with these 
the record for thermocouple 15 giving the temperature of the air 
of the chamber at one point outside the hive is also included. 
It will be observed that on several occasions the temperature of the 
center of the cluster (which shifted between thermocouples 12 and 7, 
according to the movement of the cluster during the experiment) 
rose somewhat abruptly but temporarily, not, however, reaching the 
temperatures observed at the time that the bees were placed in the 
chamber. While some of the rises may be attributed to mechanical 
disturbances, it was not always possible to determine the exciting 
cause. This is in accordance with numerous observations made in the 
work on the behavior of bees in confinement to which reference has 
already been made. Throughout the experiment, of course, heat 
production never ceased, and with the bees in this condition of 
activity it took but a small disturbance to induce them to generate 
slightly more heat. This is comparable with the periods of activity 
that have long been observed in bees wintered in cellars. 
It is more important to note that during the 12 days that the 
bees were in the respiration chamber the temperature of the cen* 
