Feb. 1, 1904.] 
THE TROPICAL 
AGRICULTURIST. 
535 
FLIES DYING ON JK.SSAMINE LEAVES. 
A CURIOUS PHENOMENON : AND THE 
GOVERNMENT ENTOMOLOGIST'S EXPLANATION. 
^ Lunugala, Jan. 9. 
Sir,— Can you, or any of your readers, 
explain whether jessamine leaves are fatal 
to the common house fly, and, if so, why ? 
Some jessamine bushes just in front of our 
house are at present bearing a heavy crop 
of dead flies, as per sample leaf enclosed. — 
VASTATOR. 
[We forwarded tlie above enquiry, with the 
leaf, to Mr. Green before publishing it and he 
kindly replies as follows,— Ed. T. A. :— ] 
Royal Botanic Gardens, Peradeniya, Jan. 12. 
Dear Sir, — The flies have not been killed by the 
jasmine leaves ; but have succumbed to a disease 
caused by a parasite fnnjius. The bodies of the dead 
flies are full of the mycelium and spores of the fun- 
gus. These flies had probably been feasting together 
upou some infected material, had simultaneously 
caught the disease, and had gone off to die together 
upon the leaves of the first convenient plant. This 
habit of congregating before death is not unusual, 
with flies. A similar case came to ray notice two 
years ago, when a correspondent sen' rue a leaf 
of a ' Malaboda ' (Myristica laurifolia) upon 
which were some thirty dead " blue dottle " flies. 
He wrote me that this leaf was one from a small 
bush growing by the side of a jungle path, and 
that each leaf was similarly ornamented with 
dead flies, so much so, that the bush looked quite 
blue. An occurrence of the same kind is recorded 
in the American publication "Insect Life" (Vol. 
IV, p. 153), in which the following paragraph 
appears : — 
" The comparative scarcity of flies of all sorts this 
summer in the District has been a matter of comment, 
whereas in neighbouring towns fliea have been nn- 
nsnally tronblesome. This anomaly may find its 
explanation in the remarkable destruction of certain 
flies by a common Empusa disease. In a recent 
stroll through the grounds of the Agricnltni'al 
Department the underside of the leaves of various 
trees was found to be quite thickly covered with dead 
flies, attached by a fungous growth. The abundance 
of the flies can be surmised from the fact that a 
single leaf not infrequently contained as many as 
eight or ten specimens. The flies, for the most part, 
belong to a common species, Pollenia nidis, which 
occurs abundantly in the tete summer on outdoor 
vegetation, but include various smaller forms, some 
of which are probably referable tc the house fly. 
The disease is not the common fungous disease of 
the house-fly (Empusa 7nu3cce), isolated cases of which 
are not uncommon in houses, but E. Americana, which 
occurs as far as known always outdoors on vegeta- 
tion, etc." 
It would be interesting to learn whether your 
correspondent has observed any local diminution 
in the number of house-flies as a result of the 
prevalence of this disease. 
The Government Mycologist has examined the 
fungus and reports that it is undoubtedly a 
species of Lmpu.ia and either identical with or 
closely allied io E. muscre. — Yours sincerely, 
E. ERNEST GHEEN. Govt, Entomologist. 
RUBBER PLANTERS AND MANUPAC 
TURERS : AND ACETIC ACID IN COA- 
GULATION. 
Jan. 9. 
Dear Sir,— In regard to the article ou 
the above subject, I do not think acetic 
acid is necessary, at any rate here, It only 
hastens tlie coagulation. T do not put acetic 
acid to the milk that comes in at 8 o'clock, 
and it is coagulated the next morning. To 
the evening rubber I put about half a tea- 
spoonful to each plate of rubber, and it is 
ready the next morning at the same time 
as the morning rubber of the same day. 
The biscuits are mixed together, and I have 
never had any picked out at home as 
inferior to the bulk. 
With regard to the form, I do not think 
the manufacturer cares whether the rubber 
is sent in biscuits, or any other form. For 
the planter the biscuit is convenient, as 
being so thin it can be dried easily, and it 
is easy to see if there are any impurities 
in the rubber. If it were found that the 
acetic acid spoilt the quality of the rubber, 
it would, I think, be quite simple to coagulate 
without it. At the same time I have only 
cured small quantities and cannot speak 
with any authority. With regard to smoking, 
I believe the rubber was sent home in big 
balls. It would have been very difficult to 
dry a big ball like this, and the ball had 
thin layers put oa of rubber, and these 
were dried by the heat, before more rubber 
was put on. The dark colour proved that 
the ball had been dried over heat, and, 
therefore gave the manufacturer a- guarantee 
that it was fairly dry. I do not know that 
this is the case, but with biscuits, not only 
do the manufacturers not insist on the 
rubber being dark, but actually pay less for 
dark biscuits. With regard to the manu- 
facturer, I do not think it would be easy 
to get estates to continue to sell together, 
where they were owned by separate pro- 
prietors.— Yours faithfully, T. 
II. 
Jan. 11. 
Dear Sir, — I have perused the article on the 
above with much interest, and, as regards 
the use of acetic acid, I may say that I 
invariably use it to hasten coagulation. On 
the various estates I have charge of, from 
which we have this year harvested close on 
25,000 lb. rubber, the use of acetic acid has 
been general, and 1 may say that our cured 
rubber has always realised top prices both 
in the Colombo and London markets. 
I am not prepired to say that the use 
of the acid affects the quality of the cured 
rubber in any way; hut until some improved 
method of coagulation is discovered, 1 think 
it will be very difficult if not impossible to 
deal with the latex in large quantities without 
using some kind of acid to hasten coagulation. 
—Yours faithfully, PLANTER. 
RUBBISHY TEAS IN COLOMBO 
HARBOUR. 
Kandy, January 13th. 
Sir,— ^Vilh reference to the annexed copy 
of Minute and Resolution passed at a recent 
meeting of the Committee of the Planters' 
Association of ("evlon in connection with 
the subject of Rubbishy Teas in Colombo 
Harbour, I enclose herein for publication 
copy of the report of the Colombo Tea 
Traders' Association referred to.— Youra 
faithfully, A. PHILIP. 
