MR. NEWPORT ON THE TEMPERATURE OF INSECTS. 
289 
before seen, the difference in a Hymenopterous or Lepidopterous insect, in the per- 
fect state, and under precisely similar circumstances, would have amounted to at 
least eight or ten degrees. From these observations it is evident that the natural 
heat of the Carabi is exceedingly low, and that their external temperature is scarcely 
more than *2 or - 3 of a degree above that of the medium in which they are living; 
and although the respiration of these insects is higher than might at first be supposed 
from the small amount of their external temperature, yet they have the power of 
bearing the privation of oxygen for a very long time, and also of supporting the 
presence of some noxious gases ; while they often reside in the coldest, dampest, and 
most unaerated situations. It was a specimen of this species that I once kept for 
several hours in hydrogen, and at the end of the observation found that it had ex- 
pired a considerable quantity of carbonic acid gas during its confinement. 
Blaps Mortisaga, Linn. 
June 26, 1834. — The temperature of this species (which is truly a nocturnal one,) 
appears to be lower even than that of the Carabus. I placed two specimens in a 
phial, the temperature of which, and of the surrounding atmosphere, was 71°; but the 
thermometer was raised only T of a degree, even after the insects had been for a 
considerable time in a state of activity. Two more specimens were then added, and 
the four insects were in a state of great activity for five minutes, when the tempera- 
ture of the phial was only 7 1°*1, that of the insects themselves 7 1 0, 4, a difference of 
only '4 of a degree above the medium in which they were confined. Thus the amount 
of power of developing heat in the Blaps, as in the Carabus , corresponds with the 
capability of supporting existence in a noxious medium, and also with its power of 
sustaining life during long abstinence. The Blaps will live for several minutes in a 
mixture of the most noxious gases, carbonic and even nitrous acid gas. I have con- 
fined one of this species in nitrous acid gas for three minutes, and it recovered in a 
quarter of an hour after being again exposed to the atmosphere. Another specimen 
was confined in nitrous acid gas for fifteen or sixteen minutes, and although it did 
not give any indications of recovering after being again exposed to the atmosphere 
for more than an hour, yet on my beginning to dissect the specimen, and after I had 
removed the whole under surface of the abdomen it began to recover, and in less than 
four minutes was so completely restored as to be able to walk about with nearly its 
usual speed. I have also confined other specimens in hydrogen for several hours, 
during which time they evolved a considerable quantity of carbonic acid gas, and did 
not appear to be at all inconvenienced by the medium in which they were placed. 
The low amount of heat in the species corresponds also with its power of going 
without food. One of this species is stated to have lived three years in confinement 
without food, and I have myself kept several individuals of this species about nine 
months fasting ; it must be remarked, however, that this was during the winter 
months, from the latter part of autumn to the following spring, and may derive some 
