200 
THE TROPICAL 
AGRICULTURIST. [Sept. 2, 190L 
thoughtful nation, if instead of drinking tlie 
fiery juice of the pahn and unboiled tank water 
they drink pure Indian tea direct from the gardens. 
The tea industry of India ein|doyfi many thousand 
Indian people, a.s well as hundreds of our own 
countrymen ; this is only one reason why it 
deserves the sympathy and help of every thought- 
ful person in the Empire. 
FIBRES AND RUBBER. 
We are again indebted to our Paris cor- 
respondent, M. Godefroy-Lebeuf, for a 
chatty letter in respect of his Rubber 
and Fibre experiences, given in our daily issue 
and Tropical Agriculturist. We may tell hiin 
that, while many experiments in Fibre 
extraction have been made in Ceylon, 
none has resulted profitably. At the time 
of coffee depression, Mr. Chas Shand im- 
provised a machine and tried all the local 
fibres availal)le, and got the best results from 
Smtseniera Zej/lanica which grows freely in 
Colombo gardens; but the margin, even in 
this case, was too narrow to allow of 
any profit. Later experiments, by a Colombo 
Syndicate of practical men, were made to 
give a full trial of locally-grown aloes in a 
machine strongly recommended by a Natal 
patentee, and which was fitted up at the 
Colombo Iron Works, supplies of aloe 
branches being brought down free by rail- 
way ; but the result was not satisfactory 
and there was an appreciable loss to the 
pockets of the gentlemen concerned. And 
yet Ceylon might well be said to be a paradise 
for the growth of fibrous plants ; and Mauri- 
tius keeps up a steady export of aloe fibre 
as much as R700,000 worth being shipped 
in one year. 
■ 
THE LAKE FLY NUISANCE. 
REPORT OF THE ENTOMOLOGIST. 
" My visit to Colombo extended from Tuesday, 
July 30th, to Friday, August 2nd, during which 
time I sludied the life history of the " Lake Fly " 
and made tlie following observations. Tlie insect 
proves to be a species of Chironomus, one of the 
aquatic flies, the early stages being passed in the 
water ot the Colombo Lake." Then follows a 
scientific description of the insect. The conclud- 
ing part of the report we quote as follows; — 
•SUGGESTIONS FOR REMEDIAL MEASURES. 
In dealing with this pest wu are fortunate in 
having a nearly complete knowledge of the life his- 
tory of the insect, and it will be poasible to attack 
it at each of the principal stages of its existence. 
The eggs, as noticed above, are laid in the water, 
anchored to some solid substance which will retain 
them at the surface, ensuring them the amount of 
light and air necessary for their development. As 
this part of the lake is kept free from floating weeds 
by a system of contracts, it follows that the deposi- 
tion of the eggs must be confined to the margins 
of the water. The removal and destruction of »11 
Seating rubbish and herbage growing in the water 
at the margins of the lake will ensure the des- 
truction of an enormous number of eggs. This will 
not prevent the .substquent deposition of fresh 
batches of eggs on the bank. But, from my ob- 
servation thai floating sticks form a favorite point ot 
attachment for the egg-masses, I think it would be 
poasible to trap the bulk of the eggs by laying down, 
in the water along the margins, bamboos lightly 
covered with brushwood. The eggs would be deposited 
on these during the night. The following morning 
the bamboos should be lifted out and left on the 
bank to dry. The heat and drying action of the enn 
would kill auy eggs deposited on these traps. The 
bamboos would be returned to the water each after- 
noon at about b o'clock. To reduoe the available 
breeding places, the smaller unoccupied islets mi^ht 
be removed. 
The larvae, living on the surface of the mud and 
being independent of gaseous air, would be unaffected 
by any application of kerosene to the surface of the 
water. The restriction of the eggs to the margins of 
the lake fixes a limit to the feeding grounds of the 
larvae, it is improbable that they would zander very 
far from their native spot. A zone of some ten 
yards from the bank, all round the lake, would prac- 
tically cover the sphere of action of the larvae. The 
removal of the mud, to a depth ot only six inches, 
along this marginal zone, will effectually destroy the 
myriads of larvae now breeding there. A shallow 
dredging, repeated twice or thrice during the year, 
will be much more effective than deeper dredging at 
longer intervals. It will be necessary to remove the 
oozy surface mud only. The larvae will not thrive 
in the firmer gravelly or sandy mud. The insects 
inhabiting, as they do, merely the surface layer of 
the mud, it may be necessary to contrive some modi- 
fication of the ordinary method of dredging to prevent 
the dispersal of this superficial layer durmg the opera- 
tion. J'osaibly some form of hand dredging might 
be employed. I am confident that a judicious system 
of dredging, on the lines here suggested, will prac- 
tically remove the nuisance or, at any rate, very 
greatly mitigate it. 
The greater number of the pupae would be des- 
troyed by the same measures that have been sng» 
gbsted far the removal of the larvae. But in this 
stage the insect is also vulnerable at a different 
point, namely at the time when it rises to the sur- 
face of the water preparatory to the liberation of the 
flj . A film of kerosene on the water at this time 
would kill any of the pupae with which it came in 
contact, and would certainly prevent the successful 
emergence of auy flies. If it is decided to give this 
plan a trial, the application should be made in the 
evening, shortly before dusk. The simplest and most 
effective way of applying the oil would be by trailing 
a rope, covered with rags or tow soaked in kerosene, 
along the surface, the ends of the rope being at 
tached to two boats which would be rowed along the 
margins of the lake at a suitable distance frr-m each 
other. The rope should be periodically recharged 
with oil. 
The adult flies are notoriously attracted by light 
and might, perhaps, be trapped by bonfires or lighted 
chulahs placed along the edge of the lake. But I 
am of opinion that this measure would not really 
repay the cost, An enormous number of flies might, 
however, be slaughtered on Dhobies' Island and at 
other places where they are known to rest during the 
day, by spraying the grass with a mixture of kerosene 
and water. 
I am most sanguine of profitable results from the 
employment of the system of dredging suggested 
above. 
E. ERNEST GREEN, 
Government Entomologist. 
Royal Botanic Gardens, Peradeniya, 10th August, 
1901. 
The Deaf Hear.— No. 479 of the Illustrated 
World of G26, Chiswick High Road, London, W., 
England, contains a description of a Remarkable 
Cure for Deafness and Head Noises which may 
be carried out at the patient's home, and which 
is said to be a certain cure. This nuniber will 
be sent free to any deaf persons sending their 
address to the Editor. 
