( 102 ) 
The little grebe, or dabehick, which has taken up 
its permanent abode in the lake, was then in 
larger numbers than now, and flocks of whistling 
teal, a bird common in the Western Province, 
visited the place. Pond herons were also to be 
seen, and kingfishers were not uncommon. Among 
the leaves of the lotus were green and yellow water 
frogs, of the kind found in low country swamps — 
this species is now extinct in the lake — which 
lived on insects and occasional little fishes. In 
and oijt among the lotus plants swam water snakes 
(the common Diya bariya of the Sinhalese) which 
kept the frogs from increasing. The lake fly was 
not then absent. It bred as now in the lake, but 
the pest was kept down by the fish. The balance 
of nature was maintained. The lake — the main 
basin — was then, of course, purer and cleaner than 
it now is. 
The gradual and complete destruction of plant 
life was not in any way due to the poUucion of 
the water. A more radical agency than the gentle 
action of sewage contamination was at work, The 
natives dug up - the rhizomes of the lotus 
which they boiled and devoured with avidity, 
and the clumps of reeds were pulled out to be 
woven into mats by the native women. The 
lily plants were dug up indiscriminately, and in 
course of time they grew fewer in number, until 
they entirely disappeared. An efForc was marie 
by the late Dr. J \V VanGeyzel, who was the first 
Municipal Councillor for the Pettah ward, and the 
late Mr. Cowasjie, to stop the wanton destruction 
of these beautiful water plants, which had always 
been regarded with admiration ; but when action 
was at last taken by the Municipal Council it was 
too late. The whole sheet of water had been 
cleared of them, and there was not a single lotus 
plant or leed left. With this spoliation a com- 
plete change came over the lake. 
SCAVENGERS OF THE DEEP.— INTRODUCTION OF 
HYDRILLA. 
The lily plants, it was recognised, helped in a 
way to keep the water pare, absorbing organic 
matter ; and the shoals of fish and the mud tor- 
toises — which were also most effectual in keeping 
the water clean— deprived of the protection they 
had had among the lotus plants, were quickly 
reduced in number, as the fine nets of the fisher- 
men now swept the whole lake. Immense quan- 
tities of fish were netted and sold year by year, 
till now there are hardly any decent sized fish 
left. Most of those now netted are undersized, 
the young fish not having a chance to grow up 
before they are captured. The lake being deprived 
of its cleansing agencies could not dispel the 
foreign matter introduced into it from a large 
city. 
Spores of Hydrilla Wiphti— which is not 
altogether a sewage feeding plant, as it is found 
growing in clear-water wells in the low-country — 
were introduced during rains or at flood time, 
and found plenty of room to grow and spread in 
the lake, from which all plant life bad been 
eradicated by various vandals. It thrived 
luxuriantly, flowering and scattering spores in all 
directions, till the weed floated thick in masse^^, 
chiefly in the main basin and the Galle Face 
section of the lake. As it was spreading in all 
directions it was considered to be a nuisance. 
It became dangerous, and practically impossible, 
for the members of the Ilowing Club t 
continue their pastime, and a syste 
matic campaign was accordingly instituted 
against it. Gangs of coolies waded out daily into 
the shallow parts and scooped the weeds up, while 
others, fia raftsj attacked the masses in deep water. 
Hundreds of cart loads were removed weekly. The 
Hydrilla flowers annually, when the buds get de- 
tached and distribute the spores. It was, there- 
fore only natural that the plant should have been 
completely destroyed in thesame way asiV;/w;)7ia5a 
lotus and the water reeds in tlie old days. Plant 
life, therefore, it must be admitted, has not de^ie- 
nerated to the species algoe through pollution of 
the lake. If given the chance, water plants should 
grow and flourish now as of old; and it would be an 
excellent thing if the Municipality were to intro- 
duce the water lily into the lake — but not theNelun 
which grows to the exclusion of all other water plan's. 
Navigation would not be interfered with in any 
way, as the frail plants do not grow thick, and only 
the flower stalks stand out of the water. Of the old 
lake plants the P^sto stratiotes is still to be found 
in various corners; masses used to collect along the 
railway embankment off the Rifle Green. Dr Willey 
is credited with having taken Spb-ogyra from the 
lake. He required the plant to demonstrate a 
lecture on Botany, and, going down to Hunupitiya 
road, he saw coolies pulling out masses of tliis 
clear- water plant. It was a plant that did not grow 
in foul water, and he thought it was a pity to take 
it out of the lake. 
THE FLY PEST. 
The statement that "in 1901 the lake developed 
a great capacity for breeding flies, because, ac- 
cording to Dr Chalmers, 'there is plenty of algre 
for the voracious larvte to live upon' " is alto- 
gether illogical. The fly, it is contended did not 
increase owing to the increase of algae, but owing 
to the lake being denuded of fish. It is a well- 
known fact that the larvis of O'liironomus, the 
genus to which the Colombo lake fly belongs is a 
tavourite morsel with the carp tribe. This is an 
important factor in the question of fisheries in 
other countries. There are several species of the 
carp tribe in our lake and it is this fish that is 
especially taken in the nets as, unlike mud fish, 
they do not take refuge in the mud and escape. 
When plant life flourished in the old lake the 
lake fly existed, but the fish kept the pest down. 
The appearance of the Colombo lake fly in large 
numbers on certain evenings, and its absence on 
other evenings, has been the subject of some 
e::quiry. Prop. Miall, F R S., (Yorkshire Col- 
lege), says in connection with the Chironomus : — 
Od, summer evenings the male flies gather in great 
swarms, often containing several thousands of indiv- 
dals, in the neighbourhood of the streams or poole 
in which the larval stage is passed. Here they per- 
form an aerial dance rising continually to the top of 
the swarm, and then slowly subsiding. Females are 
rarely seen in the swarms, and the purpose of these 
singular gyrations was long obscure, But it has been re- 
cently observed. . . that on windy evenings when the 
swarm is blown hither and thither, a certain proportion 
of females may be found among the males. A female 
fly, immediately after emerging from the water joins 
the nearest swarm, and in still weather is mated at 
once. Then she flies off to lay her eggs, while the 
male rejoins his comrades, . . , But when the swarm 
is much agitated by wind, pairing becomes difficult, 
and a number of feoialea may be forced to remain 
unmated. 
