21 
(in cases that we know to have been carefully observed 
and recorded) have been found so to affect the colour 
and size of the insects then in their first stages, that in 
their perfect state these different forms have been con¬ 
sidered as distinct species, the difference all the while 
being merely (as far as shown by the large number of 
observations taken) in unimportant respects. 
There are also differences in the colouring of some 
insects in coincidence with their spread to more 
southerly regions from our own as well as in connection 
with altitude, but these time does not allow to enter 
on now. 
We may see for our own practical purposes how 
warmth affects the development of insect-life from the 
familiar example of our Wood Ants, which on a sunny 
day will carry the pupae up to the higher part of 
the nest, and leave them just under the protecting 
sticks and rubbish until the cooler part of the after¬ 
noon, when they are all taken down again and stored 
safely out of the way of chills; and, in the case of our 
cabbage chrysalids, we may use the knowledge that 
warmth is serviceable for their maturation at once by 
clearing them out of all the sheltered nooks which, 
by reason of this requirement, we know they will be 
found in. 
The coolness and darkness of the night, or the bright 
sunshine, as distinguished from the cloudy light of 
many of our summer days, all have their effect on 
insect-life, some of which we can utilise, and some of 
which, although we cannot alter them, will benefit us, 
if we notice them, by preparing us for coming attack. 
The common Cockchafer is quiet under the leafage in 
the heat of the day, and may then be shaken down and 
destroyed; and, though we do not often suffer from 
injury caused by the grub of this beetle to the amount 
to which it ravages in Germany, yet the extent to which 
it has destroyed young pine plantations near Salisbury 
in the two last years show that we need to keep it in 
check, lest it should rise to be as severe a pest as the 
