248 Sharpies .— The Laticiferous System of Hevea 
One rubber estate in Malaya adopted Fickendy’s methods and soon 
began to suffer from attacks by Xyleborus parvulus (shot-hole borer). 
When the attacked trees were inspected it appeared that the bark-scraping 
was the fundamental cause of the trouble. The explanation was unsatisfac¬ 
tory in the absence of experimental data, so an experiment was started to 
test the effect of bark-scraping upon rubber trees, with a view to elucidating 
whether such treatment makes the trees more liable to attack from fungi and 
insects. For the experiment 30 well-grown, 5 years old, untapped trees 
were taken. They were divided into five blocks, each containing six trees. 
The blocks were marked t A, 1 B, iC, 2 A, and 2 B. Block 1 C acted as 
control to Blocks 1 A and 1 B. The treated trees were scraped on 28/5/15, 
over half their circumference, to a height of four feet from the ground. Care 
was taken that the laticiferous layer was unharmed, no latex exuding after 
the scraping. 
Block 1 A. Scraped heavily, the green cork-cambium being removed. 
The scraped area was watered daily, with a hand-pump, for a few minutes. 
Block 1 B. Trees scraped lightly, the green cork-cambium (phellogen) 
being left intact. Watered as 1 A. 
Block 1 c. Unscraped, but water applied as 1 A and 1 B. 
Block 2 A. Scraped as 1 A, but no water applied over scraped areas. 
Block 2 B. Scraped as 1 B, but not watered. 
Blocks 1 A, IB, and 1 C were treated with water daily in order to 
prevent a spell of dry weather interfering with the progress of the experi¬ 
ment. The results given below of the treatment are most interesting. 
A daily examination of the trees was made, the dates given below indicating 
the day upon which the attacked trees were first noticed. 
Examined 1/6/15. Block 1A showed one tree badly attacked by 
boring beetles, the latex streaming down the bark. The remaining five 
trees in this block also showed attempts on the part of the insects to pierce 
the bark. None of the trees of the other blocks showed any sign of attack. 
Examined 6/6/15. One tree in Block 2 A very badly attacked by 
borers. 
Examined 11/6/15. One tree in Block 1 B attacked by borers ; another 
tree in Block 2 A showed signs of a bursting of the bark, from which latex 
was exuding. « 
Examined 14/6/15. A third tree in Block 2 A showed signs of the bark 
bursting, with exudation of latex. 
Examined 30/6/15. One tree in Block 2 A shows cracks in bark with 
latex exuding. 
From 28/5/15 to 2/6/15, there was no rain; from 2/6/15, daily showers 
were the rule. 
Thus/out of twenty-four treated trees, five were attacked as a result of 
the bark-scraping. Of these, four were heavily scraped and only one lightly 
