260 
MR. NEWPORT ON THE TEMPERATURE OF INSECTS. 
made in the usual manner, by placing a considerable number of insects of the same 
species together, and then introducing the thermometer among them. But it was a 
few days previously to making these observations that I first noticed the interesting 
fact, that each individual insect maintains its own temperature, which is perceptible 
externally by the thermometer, and that the amount of this varies in the different 
conditions of the same insect. The observation was first made on the larva of Sphinx 
Atropos, Linn., and on that of Pygcera bucephala, Steph., as will presently be 
shown. 
During the time I have been engaged in preparing the present communication 
I have become acquainted, through the kindness of Dr. Forbes of Chichester, with 
the recently published views of Dr. Berthold, of Gottingen, who has made a series 
of observations on the temperature of cold-blooded animals*, and among them several 
on insects, somewhat similar to those which I now have the honour of submitting to 
the Society. But excellent as are the views of that gentleman, he does not appear 
to have paid sufficient attention to the conditions of activity or rest in the insects at 
the time of making his experiments, and consequently has omitted to observe the 
important fact of the existence of a distinct temperature of body in individual in- 
sects -f-, and also those circumstances which augment or lessen its amount, and has 
estimated the temperature by placing many individuals together, which, as will pre- 
sently be seen, is open to several objections. Dr. Berthold has, however, anticipated 
me in the expression of one opinion, unto which we have mutually been led by our ob- 
servations, viz. that at all events the higher classes of invertebrated animals ought not 
to be considered as cold-blooded, since it is found that under certain conditions they 
have a temperature of body higher than that of the surrounding medium. Hausmann £ 
made an observation as long ago as the year 1803, which ought to have led to a proper 
understanding of the nature of the temperature of insects. He placed a perfect spe- 
cimen of Sphinx Convulvuli, Linn, in a small glass phial when the temperature of the 
atmosphere was 1 7° Reaum. (70°'25 Fahr.), together with a small thermometer, and at 
the expiration of half an hour the temperature of the phial was 19° Reaum. (74 °'7fi 
Fahr.), but soon afterwards he found that the temperature of the phial had sunk again 
to the previous standard 17° Reaum. He then repeated the observation with six spe- 
cimens of Carabus hortensis, Linn, with similar results. From what will subsequently 
be shown respecting the temperature of Carabi, which do not develop so large a 
quantity of heat, it is very probable, as suggested by Dr. Berthold §, that the results 
obtained by Hausmann arose from the bottle which contained the insects being touched 
by the hand of the operator. Dr. Berthold has observed this in his experiments, 
and I have constantly remarked the same thing myself when proper care was not 
* New Experiments on the Temperature of Cold-Blooded Animals, by A. H. Berthold, M.D., Gottingen, 
1835. 
f Ibid. p. 36. Experiment 59. 
X De Animalium exsanguinum Respiratione. Gotting. 1803. p. 68. 
§ Neue Versuche, &c., p. 11. 
