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the “Pine-shoot Tortrix Moth” (Retinia buoliana, Schiff.). 
The female deposits an egg at the extreme point of a shoot, near 
the base of the terminal bud, in July. A caterpillar appears in 
the course of a few weeks and gnaws a small wound at the base 
of the bud. This causes a flow of resin in which the caterpillar 
passes the winter. When growth begins in spring the caterpillar 
bores into the shoot and eats its way upwards along the pith. 
In many cases the leading shoot is killed. This results in the 
upward growth of a whorl of side branches, and eventually 
several leaders, all appearing at a sharp angle with the main stem. 
But at other times the leading shoot is less seriously injured, 
probably through some tragedy overtaking the caterpillar. 
It is so weakened, however, that it cannot maintain an erect 
position and bends over sometimes at right angles with the trunk 
and sometimes lower still. In the case of very considerable 
weakening the shoot may eventually break off by reason of its 
own weight but in other instances, once the caterpillar disappears, 
the natural vigour of the tree enables it to set about repairing the 
injury. The wound heals and the point of the shoot turns up- 
wards. Instead, however, of turning upwards at right angles 
in a new vertical plane it takes a distinct curve until it is approxi- 
mately over the centre of the lower part of the trunk, then by a 
sharp turn quickly assumes a vertical position. This all occurs 
in the course of a few weeks and probably passes unnoticed. 
The curve, however, develops with the growth of the tree and 
becomes very noticeable a few years later. As time goes on there 
is a distinct tendency for deformed trunks to straighten, for 
growth is much more rapid on the inside than on the outside of a 
curve. Numerous deformed trunks are doubtless removed in 
the course of thinning, but some probably remain until the crop 
is mature and this may be one of the reasons for irregularities of 
structure that are sometimes found in planks. 
It has been suggested that the curve in the trunk is due to the 
removal of the natural leader and by a side branch turning upwards 
to take its place. There is, however, plenty of evidence to prove 
that in healthy young pines which lose their leaders, there is 
a distinct tendency for not one but a number of side branches to 
upwards at a sharp angle and in some cases it becomes 
necessary to thin them out in order to preserve a single trunk. 
Moreover, the curve often occurs midway along the annual 
growth, a point at which it would be very unlikely that a side 
shoot would appear. In order to make sure that there had been 
no interruption in the original leading shoot of the specimens 1n 
question, a longitudinal section was cut through a curved t 
from a point six inches below the curve to a similar distance 
above. The pith was then traced and found to be continuous, 
but at the lower bend it had been injured to some extent. 
whorl of branches occurred at the lower bend and the next whorl 
was immediately above the higher bend. The lower part of the 
trunk had 14 annual rings and the upper part 12 annual rings. 
