MR. NEWPORT ON THE TEMPERATURE OF INSECTS. 
319 
blood which is steadily submitted to the influence of the air in the respiratory organs 
is perhaps greater in the latter than in the former instances. This circumstance may 
also account perhaps for the smaller amount of heat generated by the larva in its 
earlier than in its latter condition, although the number of its pulsations is more than 
double in the earlier than in the latter period. In the full grown larva the pulsations 
are steady and full, with much power, but in the earlier state of the larva they are small, 
rapid, and intermitting. From these circumstances we may fairly infer that the 
quantity of heat developed is more dependent upon the quantity of respiration than 
upon the velocity of the circulation. 
3. Digestion. 
The influence which the process of digestion exercises over the production of heat 
is very considerable. We have before seen that in the larva the greatest amount of 
heat is produced after the insect has fed, or while it is feeding and becoming 
much excited. It is at these periods that it deteriorates the greatest quantity of air, 
which quantity is then necessarily required during its respiration in assimilating 
the new matter which has just been taken into its circulation through means of the 
digestive process. In the perfect insect the circumstances are exactly the same, its 
temperature is greatest after it has fed, and is then exerting itself, and at that time 
it respires the greatest quantity of air. On the other hand, when the insect is fasting, 
the quantity of heat evolved by it, even during great exertion, is much diminished, 
while the quantity of air consumed is smaller than the quantity consumed under 
similar excitement after it has taken food. 
4. Gaseous , or Cutaneous Expenditure of the Body. 
The cutaneous expenditure of the body is closely connected, both with the digest- 
ive process and with the regulation of the temperature of the insect. It is seen in 
the observations on Melolontha solstitialis and other species, that the amount of 
gaseous expenditure is exceeding great, and that after the temperature of the insect 
has been raised to a certain amount, a profuse perspiration breaks out, which is the 
natural cooling process of the body. The pulse also is considerably affected by it, 
as shown in the larva of the Puss Moth, which had been subjected to high tempera- 
ture, and which soon became bathed in perspiration. Table X. No. 1 and 2. The 
exact correspondence which exists between the quantity of gaseous, or cutaneous ex- 
penditure, acceleration or subsidence of the pulse, increase or decrease of weight, 
and quantity of respiration in every period of the larva, pupa, and perfect state, is very 
remarkable. The quantity appears to be at its maximum in the very active perfect 
insect, and is greater than in the larva, or in the pupa, in which it is at its minimum 
when the pupa has the smallest amount of respiration; but in all cases it is least 
during the state of most complete inactivity. In the common Hive Bee in a state of 
activity the amount is prodigious, and very soon becomes evident, if the bee be con- 
fined in a very small glass phial, closely stoppered, and kept in a state of excitement. 
The perspiration from the insect is then condensed upon the interior of the phial, and 
if several bees be confined together, the bodies of the little insects themselves become 
