356 
Proceedings of Royal Society of Edinburgh. [sess. 
in one season may, after hibernation, still further proceed to a new 
season’s reproduction. 
3. Hibernation takes place in the month of November, and in a 
season of average temperature ends in March; in exceptionally 
mild weather even earlier. 
4. Egg-laying takes place in all months from April (in a very 
favourable season even in March) to September inclusive. 
5. As adult beetles may be met with during all this period, the 
length of time necessary for individual development loses some of 
the significance that up till now has been assigned to it in relation 
to exterminative measures, because a comparatively limited flight- 
period being disproved, corresponding limited and definite swarm- 
periods can no longer be relied on. 
6. Still, limiting our view to one cycle and the earliest laid eggs 
of that cycle, the generation is typically a yearly one. 
7. As the first imagos issuing in the summer as a result of eggs 
laid earlier in the same year are not immediately able to proceed 
to an efficient copulation, but require some time for ripening, there 
is little likelihood of there being in our climate two generations in 
direct descent in one calendar year. 
On these conclusions, and the knowledge derived from the breed- 
ing and observation of the species, we found the following 
Preventive and Remedial Measures. 
The great means the forester has in proceeding against these 
pests once they have got to work is the preparation of catch-trees 
or decoy stems. These will be sickly plants, or trees left here 
and there in nursery or plantation; or plants can be artificially 
weakened and left standing, or an older tree can be cut down and 
allowed to lie as a breeding place. In consequence of the long- 
continued life and egg-laying, such trap-plants must be arranged 
and visited and renewed at intervals throughout the whole year 
from March till October. 
These trap trees will be barked or removed before the enclosed 
brood has reached maturity and their contents in the shape of 
larvae or pupae destroyed. 
