Apr, 28, x»2s Studies on the Temperature of Individual Insects 
283 
Tabi^B II .—Body temperatures of bees at various air temperatures 
Air tem¬ 
perature. 
Average 
body tem¬ 
perature. 
Difference 
between 
body and 
air tem¬ 
perature. 
Maximum 
body tem¬ 
perature. 
Minimum 
body tem¬ 
perature. 
Number 
of bees 
pierced. 
5-5 
10 . 2 
4*7 
14 
8.5 
100 
21.4 
25. 8 
4.4 
31 
22 . 0 
100 
27.0 
29. I 
2 . I 
30 
28. 5 
54 
30*5 
32. 0 
I-5 
-34 
31-5 
100 
35-0 
35-1 
. I 
37 
34.5 
100 
39-5 
39*5 
> .0 
42 
38.0 
100 
43*5 
43*6 
. I 
44 
42.5 
100 
$2. 0 
46. 0 
—6. 0 
48 
45-5 
100 
58.0 
46.4 
—II. 6 
48 
45-5 
II 
That bees are capable of regulating their temperature for a short 
period of time was shown by the fact that when bees were placed in the 
temperature box at 52^ and 58^ C. their body temperature did not at 
once correspond to that of the air, as it did from 35® to 44^, but was 
lower. After the bees were exposed to this temperature for about 25 
minutes, their body temperature approached nearer that of the air 
temperature. After they were in the temperature box for 30 minutes, 
they were dead and had the same temperature as that of the air. A few 
bees were tried at a low temperature —10® to +21°, and it was noted 
that the temperature of the body fell with that of the environment. 
By handling the bees in individual cages they were not excited before 
piercing. The space allotted to each bee was large enough to permit it 
some movement, but not large enough for it to make use of its wings. 
Throughout the entire experiment only two bees. No. 62 and 71, in 
Table I, were observed to be fanning. They were immediately pierced 
and found to give a reading of 8° C. above tib'at of the room, while those 
not fanning had a temperature about 4.6° above the air temperature. 
The bees were pierced at a low temperature and in the individual cages, 
so that the heat produced by the fanning was conserved, thereby raising 
their own temperature. 
When bees were exposed to the temperature of 5.5® C., they were 
taken into the room in groups of 15. A period of three minutes elapsed 
before the piercing of each successive bee to permit the thermocouple to 
return to room temperature. After the piercing of about the six^ bee 
the remainder of them became motionless but were easily revived by 
holding them in the hand for a few minutes. After a group of 10 ^^es 
was kept in the room for a period of two hours they were pierced, and they 
gave an average temperature of 2° above the room temperature. Adter 
the bees were kept at this low temperature for 48 hours they were dead 
and recorded the same temperature as the surrounding air. The bees 
may have died from either starvation or from cold. 
When readings were taken at “room temperature” the work was 
done in the laboratory and the temperature varied from 19.5° to 24® C., 
with an average of 21.5®. The bees were brought into the laboratory 
in groups of 10. At all other temperatures, witli the exceptions of 52® 
and 58®, the bees were used in groups of 25. 
As the air temperature was increased, the difference between the body 
temperature of the bee and the temperature of the air decreased until at 
