MR. NEWPORT ON THE TEMPERATURE OF INSECTS. 
281 
the thermometer so very rapidly, it is fair to suppose that the insect parts with it with 
nearly equal facility, and that a very large proportion evolved passes off to the sur- 
rounding atmosphere or medium in which the insect is inclosed, and that when such 
medium is of given small extent its temperature becomes raised as well as that of the 
insect, and is appreciable by the thermometer. This is in reality the case ; and 
Dr. Burmeister* has already imagined it to be so, but he does not appear to have 
made any observations of his own in order to prove it, but refers to the observations 
before noticed by Hausmann^. I remarked the fact during my earlier observations 
on the temperature of insects in 1834, when endeavouring to ascertain the actual 
amount of temperature in the common Humble Bee in a state of rest and in a state 
of great excitement, and when endeavouring also to ascertain whether the amount of 
temperature in a single insect is equal to that of an indefinite number of individuals. 
I had long suspected that this could not be the case, and that, for instance, the tem- 
perature of a hive of bees in winter, stated by Huber to be equal to 80° Fahr., could 
not be equal to that of a single individual at the same period. Previous observations 
had induced me to believe that the temperature of a single insect is only a few degrees 
above that of the medium in which it is living, and that the actual heat of the insect 
is increased in proportion to the amount of its respiration ; that when an insect is at 
rest its temperature is comparatively low, and that it becomes greatly increased during 
violent activity ; and further, that a number of individuals confined in a given space 
can raise the temperature of that space to a great amount. With these views I in- 
closed a single female of Bombus terrestris in a glass-stoppered phial of three cubic 
inches capacity, having first noted the temperature of the atmosphere within the phial, 
and of that of the external atmosphere immediately around it, both of which stood 
at 66 0, 9 Fahr. The bee was allowed to remain about five minutes in the phial in a 
state of great activity, and its temperature was then taken by pressing the bulb of a 
thermometer against its abdomen. The mercury rose to 73°'4 Fahr., or 6 0, 5 above 
the temperature of the atmosphere, while the temperature of the atmosphere of the 
phial was raised to 68°‘2 Fahr., or 2 0, 3 above that of its original temperature. Three 
other individuals of the same species were then added, and the whole four continued 
in a state of excitement until the mercury rose to 74°‘5. It was thus proved that a 
single individual when excited raises the temperature of the surrounding medium, 
and that several individuals collectively will increase the temperature of that medium 
beyond what it could possibly be increased by only one. 
In the next experiment, the atmosphere being 69°‘4 Fahr., five individuals of the 
same species were confined in the same sized phial as the one just employed, and after 
remaining in a state of great excitement raised the temperature of the phial to 7 2 0, 5, 
a difference of 3°T, while the temperature of the five excited bees was 76°‘3. In an- 
other experiment, when a single bee was allowed to remain at rest with the thermo- 
* Manual of Entomology, p. 403. Translated by W. E. Shuckabd, Esq. M.E.S. 1836. 
f De Anim. Ex. Respirat. p. 68. 
