x] Beetles 109 
when it is most susceptible, viz. just as it pushes its 
way through the ground. The adult beetles do the 
most damage in this case. As soon as the young 
plant appears they begin to feed on the seed leaves, 
then on the heart of the plant, and so destroy it 
entirely. In this way whole fields are eaten bare and 
have to be resown. 
The last brood of beetles formed in the autumn 
hibernate through the winter in crevices or under 
leaves. When the warm weather of spring begins, 
usually at the end of May or beginning of June, they are 
roused from their slumbers and are prepared to enjoy 
themselves at the expense of any young turnip plants 
which may be available. 
After a time the beetle lays its eggs on the under 
surface of the rough leaves of any turnip plants which 
are not destroyed, or on the leaves of other plants of 
the same order such as charlock and hedge mustard. 
From the eggs small yellow larvae hatch and at once 
commence to feed on the rough leaves by getting 
inside them and eating the green portion between the 
two skins. In this way colourless marks are found on 
the leaves and by holding them up to the light the 
young larvae can be seen in them. In about a week 
they come out and bury themselves in the ground. 
Here they change into pupae and from these the beetles 
are formed in about a fortnight (see Fig. 32). These 
then feed on the turnip leaves, especially of the younger 
plants when the field has been resown. It is in hot dry 
weather that the attack is worse, as this favours the 
development and spread of the beetles. They do not 
like wet weather and consequently less damage is done 
in a wet spring. Curtis says they are attracted by 
