THE ENTOMOLOGIST. 
Vou. XII.] JUNE, 1879. [No. 193. 
CONSIDERATIONS AS TO EFFECTS OF TEMPERATURE 
ON INSECT DEVELOPMENT. 
By E. A. Onmerop, F.M.S. 
In the great difficulty of gaining information as to circum- 
stances accompanying insect appearance in abnormal quantity, 
it seems worth while to consider whether something more might 
not be learnt about insect life (as it most certainly might about 
plant life) by greater observation of ground temperatures. 
There are certain atmospheric conditions, both as to amount of 
moisture and warmth, well known to entomologists, and which 
can be proved to affect development in various ways, but the 
popular ideas on these matters (and, unfortunately, too often 
amongst those most practically concerned in their effects) 
frequently lead exactly in the wrong direction; if we could, 
therefore, gain some exact data of temperature at the surface of 
the ground and a foot or two beneath it (as far down, that is, 
as insect presence might be presumed usually to exist), it might 
be very useful. 
With regard to simple continuance of larval existence during 
cold as severe and as long continued as it can be ordinarily 
subjected to in this country, the last winter showed us that the 
larve of many of our various injurious insects (and notably 
those of Cetonia aurata, the rose chafer, which, from its 
succulent nature and great size might be supposed both to feel 
and to show injuries from frost very readily) are to all appearance 
uninjured by a temperature low enough to freeze the ground into 
a firm mass, and ranging from somewhat below nine degrees (that 
is, twenty-three degrees of frost) on the ground level, to about 
thirty-two degrees (that is, what is commonly known as freezing) 
a 
