276 
Journal of Agricultural Research 
Vol. XXIV. No. 4 
Davy (.jt) was the first to give the internal temperature of an insect. 
An incision was made in the body and the bulb of a very small mercurial 
thermometer was inserted. He obtained the following results; 
J 
Air tem¬ 
perature. 
Insect tem¬ 
perature. 
/ 
Blatta orientalis . 
°c. 
28.3 
23-3 
16. 7 
23-9 
24*3 
22. 8 
26. 6 
® c. 
23-9 
23-9 
22. c; 
24.4 
25.0 
23. 0 
25.8 
Do. 
Gryllidae. 
Vespidae. 
Do. 
Dampyridae. 
Do. 
Nobili and Melloni (75) were the first to use electric methods in deter¬ 
mining the temperature of insects. They used the electromotive force 
developed when the junction of wires of different metals‘of a common 
circuit are at different temperatures. They used bismuth and antimony 
wires. One of the thermocouples was in contact with the insect body; 
the other couple was free. They made a series of experiments on the 
temperature of larvae, pupae, and adult butterflies. Their conclusion 
was that the temperature of the insect was higher than that of the sur¬ 
rounding air. 
Mussehl (ij) ascertained that single bees became motionless at 5® R 
(6.25® C.) while they did not suffer from cold in the colony with the 
temperature of the hive at — R, (—1.25*^ C.). 
Newport (14) used a thermometer of small caliber with a cylindrical 
bulb about one-half inch in length. The thermometer was placed be¬ 
neath the insect and was as completely covered by the abdomen of the in- 
,sect as possible. A second thermometer which had been carefully com¬ 
pared with the first was placed at the same level with and a short distance 
from the first one. The temperature of the insect was taken on the exte¬ 
rior and was always lower than that of the interior. He stated that the 
internal temperature was seldom if ever more than a degree and a half or 
at the most two degrees above the external temperature. The following 
dre some of his results showing the difference between the air temperature 
and the external temperature of the insect: 
Temper¬ 
ature 
of air. 
Body tem¬ 
perature. 
Temper¬ 
ature dif¬ 
ference. 
Boftibus tertestfis . 
66 . a 
•F. 
73-4 
76. 2 
73*4 
76. 2 
77 -S 
71-5 
6. 5 
Do.. 
66. g 
9-3 
6. 5 
Do. 
66. 9 
Do. 
y 
69.4 
68. 0 
6.8 
Do. 
9 * 5 
3 * 
Botnbus IcLpidarius . 
68.0 
0 %j 
At the time of taking the foregoing readings the insects were in an 
excited condition. 
