364 
THE TROPICAL AGHICULTURIST. [Nov. 2, 1903. 
much more limited than it is now. Many pests 
where they get an extended area of cultivation 
and find a continuous plant to breed in such as 
tea affords alter their habits very considerably, 
and very often increase and multiply to a greater 
extent than they did in their original home. I 
don't know if there is any point upon which 
any member wishes information ? 
The Chairman -.—Is it literally only the shot- 
hole borer you find in tea ? 
Mr. Green :— It occurs also iiiGuava, Grevillea 
and Arnatto. I have found shot-hole borer not 
only in living tea but in dead tea. I have found 
several species which only go for dead wood. I 
suppose you have all acquainted yourselves with 
how it acts in a tea bush. It goes in at a node 
hole, and each little infection is quite distinct 
by itself from the next one. It does not turn up 
and down the stem When it gets into one hole 
it makes two or three little galleries, and the 
female beetle lays its eggs there and its young 
are brought up. The female parent then vacates 
the hole and probably goes off and makes a series 
of channels in another hole. There is always an 
Interval between the several infections up the 
stem, and it is quite a chance if in pruning you 
discover it is there. If you cut between the 
nodes you would have no idea it was in the stem. 
You have to cut from the points affected to 
notice the borer. If you cut between the nodes 
you cannot be sure if he is above or below. 
The Chairman : — Does he work up or down. 
In a newly-affected bush he usually begins on the 
red wood. 
The Hon. Secretary :— Don't you think they 
were in the stem first as regards clearing ? 
Mr. Green : — No. Clearing in tea corresponds 
to red wood. In nurseries for instance you will 
find it in the stem first. But when it attacks 
clearing you will find nearly always it is in the 
red wood first. 
Mr. Shelton-A&ar : When a tree is pruned, 
how long does it take the beetle to vacate the hole 
or die ? 
Mr. Green : — If the prunings lie on the ground 
what happens is that after a certain time the 
parents (the parent beetle may or may not be in 
these prunings) beetles begin to fly away. There 
will be a certain amount of eggs, young grub and 
pupae of the beetle in the prunings, and those 
less than three-quarters grown will die, and those 
of three-quarters and above will mature and grow 
out of these prunings, but will take a certain 
time to do so. Burning is undoubtedly the best 
way to get rid of the borer because you can burn 
them right away off the bush. I am not averse 
to burying if it is properly performed. The way 
to bury prunings is to dig large holes before you 
prune all the tea, and have the prunings swept 
right in and earth put on the top of them. 
The Chairman:— How mucli earth. Three or 
four inches? 
Ml'. Green : I should say 6 to 9 inches at the 
least, and a little lime or basic slag is a good thing 
to add to it. Eut th^t is getting out of my pro- 
vince. I am infringing on Mr Caruthers' province ; 
he is against burying because it affects the spread 
O'- root disease. You will have to decide that for 
yourselves ; v/hether the risks fiom borer or 
root disease are likely to be greatest. 
In reply to another question Mr. Green said the 
male beetle never left tbe gallery but the 
female beetle flew away and made other holes. 
Mr. Geo. Benzie:— Do you recommend burning 
to anything else? 
Mr. Green :— Personally I do. Looking at it 
from the point of getting rid of the shot-hole borer 
I say jes. But the other matter is for the agri- 
culturist to decide. 
The Chairman ;— Has any gentleman any fur- 
ther question to ask? 
Mr. Green :— Anything in the life history of 
the insect you don't understand? I am always 
very glad to explain that. 
The Chairman :— Well, Mr. Green, we thank 
you very much indeed. You have filled us with 
hope. I must say I thought it very much worse 
than you seem to regard it. 
Mr. Green:— I do not wish to minimise the 
importance of the pest in any way. My- 
opinion is that it is not a pest that will en 
danger the tea industry in any way. 
The Chairman :— I think we should pass a 
uanimous vote of thanks to Mr. Green for his 
kindness in coming here and giving us so much 
valuable information. (Applause.) 
Mr. E. M. Hay :— I have much pleasure in pro- 
posing a vote of thanks to the Chairman for the 
very able manner in which he has presided and 
carried on the business today. (Applause.) 
This terminated the meeting. 
THE INDIAN MICA INDUSTRY. 
[FROM A CORRESPONDENT.] 
Miea is one of the best koown of the common 
minerals. It forms an interi^ral part of granites, 
gneisses, and many of the schistose rocks, and 
is readily recognised owing to its mode of occur- 
rence in glittering plates of various colours, and 
to its not readily deco.nposing, as many other 
rock-forming minerals do, when exposed at surface. 
Although found in great abundance in nature, 
commercial mica has a considerable value, the very 
best varieties often realising a price of £400 a 
ton. To be of any commercial value, the mica 
plates should be several inches square, and occa- 
sionally " books " of mica are niel: with five feet 
long by three feet or more wide." The occurrence of 
large sheets, which can be mined or quarried at 
a profit, is of course very exceptional, and there 
are not more than half-a dozen localities in the 
world where mica mining is carried on as a regular 
industry. Large plates of mica are often found, 
bat it is very rare indeed that they are free 
from the fl ; ws and discolourations which render 
them worthless in the market. 
CHARACTERISTICS OF MICA. 
The chief characteristics of all the micas is their 
more or less perfect cleavage, which permits the 
mineral to be split into films of great thinness, 
and the elaslioity of the plates. Mica is capable, 
moreover, of standing very hii;h temperatures, and 
it is a bad conductor of eleciricity, which gives it 
a great value in all electiical appliances on account 
of its high in.'sulating pmperties. 
There are many varieties of liiica, but they are 
all more or less essentially silicates of alumina 
with potash, soda, and magnesia in difllerent pro- 
portions. There are only three varieties of mica 
which are of commercial value, the nio.st important 
of which is muscovite. This is an almost pure 
silicate of alumina, and potash, and usually 
colourless, but occasionally of a deep rnby or 
olive green shade. It is often tinged with inclu- 
sions of iron compounds, and very subject to smail 
joints which traverse the faces of the plate^ and 
divide them into triangular pieces. The valuable 
ruby mica of Bengal, the olive green mica of 
Madras, and the amber mica of Brazil all consist 
of muscovite. 
