290 
MR. NEWPORT ON THE TEMPERATURE OF INSECTS. 
explanation from what is now known with regard to the condition of insects during 
the season of hybernation. Yet I have also kept this insect nearly three months 
without food during the summer, the season of activity, but it has generally died at 
the expiration of that period. 
These observations on different species will sufficiently show the great difference 
which exists between volant and creeping insects, in the power which they possess of 
generating heat, while, comparing all the physiological conditions of the species with 
each other, they seem to point to the source or cause of the development of heat. Thus 
the amount of heat is found to approach very nearly in volant Coleoptera to the amount 
in Hymenoptera. In both these tribes of insects the organs of respiration are of 
large extent, and the quantity and activity of respiration in both are great, while the 
quantity of heat developed appears to be in proportion to the quantity of respiration. 
Further, these observations lead to the conclusion that some of the volant Coleoptera 
( Melolonthce ) have a higher temperature, even in a quiescent state, than some of the 
terrestrial Coleoptera in a state of moderate activity, while the amount is increased 
in a much greater degree in volant insects in a state of activity, than in those Cole- 
optera which live entirely on the ground. It also appears that the temperature of 
Crepuscular insects, Melolonthce , Sphinges, See. is lower than that of the diurnal Hy- 
menoptera, and this we might naturally expect would be the case. Crepuscular in- 
sects having, compared with their size, a lower degree of respiration than Hymeno- 
pterous insects, nearly all of which are diurnal species, and bear the privation of atmo- 
spheric air with greater difficulty than any other tribes. 
