51 
Indian Forest Records. 
[Vol. VIJL1. 
severed ends stow dwarfed vessels ; if nearing completion it may display 
a very localised effect, that is difficult to detect, or it may be stimulated 
to produce a diffuse mass of small pores extending into the outer wood. 
Often the later excavations of the larva remove the abnormal portions of 
the pore-ring, and produce a clean-cut effect on its boundaries, that 
simulates an emargination of a normal pore-ring. In doubtful cases the 
best criterion is the pore-ring of the first year’s overgrowth. 
3. After Pore-ring Formation. A larva which does not bore into 
the wood until after the zone of pores and a certain amount of the small- 
celled wood is formed, cuts through the pore-ring of the current year in 
the same way as it cuts the rings of previous years and the effects ate 
indistinguishable. But the initial injury to the cambium causes the 
production of a line or narrow zone of large pores resembling a false 
ring and extending for a short distance on either side of the wound. 
The presence of a short false ring is very common in fast grown trees, 
but it is often absent in suppressed or nonvigorous trees. In the 
false ring the medullary rays usually run straight through without 
deflection, but in a true ring several of the alternate rays are slightly 
diverted and form an angle at the junction of the “ autumn ” and 
“ Spring ” wood. 
Overgrowth or Callus-formation .—In fast grown trees no difficulty 
arises in the dating of a beehole ; the annual ring is broad and the callus 
formation is rapid and easily visible. The sapwood chamber is filled 
with callus and two lobes extend into the mouth of the beehole during 
the following year after the moth has emerged. It may be safely 
assumed that emergence in the majority of cases occurs during the hot 
weather, i.e., before pore-ring formation starts, and the date of 
emergence can therefore be used to fix the date of attack in doubtful 
cases. In suppressed trees some years may elapse before lobes of 
callus enter the cavity; in such cases the annual ring of the year of 
emergence is often recognisable by a departure from the parallel of 
concentric arrangement of the preceding normal rings. The attack 
of the insect usually stimulates increased growth in width at a short 
distance from the site of injury, which persists for several years. 
Examples of this type are more easily dated at a distance of an inch 
or two from the scar than at the beehole itself. [Vide Plate VI], 
The year of attack is recorded as that following the first normal 
pore-ring or that preceding the year of callus formation, whichever is 
the more readily determinable. When it is not ascertained whether 
the larva attacked before or after pore-ring formation the error in the 
date of attack is within the limits of ^ 1. 
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