310 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
require some time for ripening, even in a year favour- 
able as regards temperature and weather conditions, 
there is little likelihood of there being two generations 
in a calendar year. 
On these conclusions we found the following preventive and. 
remedial measures :— 
A great means the forester has in proceeding against this pest, 
once it has 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 inclusive. 
These catch-trees or traps must be barked or removed before 
the enclosed brood has reached maturity, and their contents, in 
the shape of larve or pupz, destroyed. My experience is that, 
where ripe larvee have been exposed to the light and weather by 
a removal of the bed-coverings, they rarely complete their develop- 
ment, yet it is safer not to give them the opportunity. Where 
the barked stems are not removed, special care must be taken 
that beds deep in the wood are not overlooked, but their contents 
destroyed. (This must specially be attended to in the case of 
P. pini, whose beds can be found deep in the alburnum.) 
As thin twigs may be used for breeding in, these, if not removed 
and burnt, must be slit up for the destruction of enclosed grubs 
or pups. Their yielding to pressure, here and there, will be a 
guide to their having been tunnelled. 
I am certain, from my experiments, that where notatus is 
plentiful (and in such cases perfectly healthy plants can be 
attacked and will succumb), collecting the imagos would prove 
very serviceable. This measure could be certainly adopted in 
nurseries with good results. The beetles would require careful 
looking for, however, owing to their protective coloration ; but 
favourite places for them are below the whorls, at the bases of 
the bifoliar spurs, and lying between the buds. I have pointed 
out that imagos may be found during many months, and new 
imago issue also, yet the intervention of winter will give rise to 
a certain seeming periodicity of imago appearance. Collecting, 
