261 
that there were 90,000 to an acre, or about 22\ millions to the 
whole plantation. c 
Calculating the sexes to be equal, this would give at the esti 
mated number of eighty eggs to a moth, the enormous amount of 
nine hundred millions^ of caterpillars) on the estate at the next 
breeding season, within a period of four months from their first 
being noticed. The estate coolies being insufficient to keen 
down the pest, though destroying 300,000 caterpillars a day 
the Selangor Government assisted by supplying additional 
labour and m a few months the plague was so reduced as to be 
rn.3.ri3-^68, bie* 
Beside handpicking, other means were tried to destroy the 
insects on a large scale. Butterfly nets were supplied to bovs 
who caught the moths, and though a number were killed like 
this, the value o± this work was reduced by the fact that the 
moths which were most readily caught were those that had 
finished laying their eggs, the more active ones fresh from the 
chrysalis escaping. Experiments were tried with London purple 
and sulphide of potassium, tuba root and smoking with 
sulphur, but none of these were of any practical result, 
London purple which has been used to kill caterpillars in 
other parts of the world with so much success, has here proved 
useless, for what reason I cannot guess. 
I have tried it on many kinds of caterpillars and find that it 
either acts so slowly that the caterpillars can easily free them 
selves from it, or does not kill them at all. Sulphide of Potash 
m solution is more rapidly fatal and with a proper syringing an- 
paratus, might be utilized with good results in similar outbreaks 
especially as besides being fatal to the insects it is beneficial also 
to the plant as a manure. Tobacco water, soap, tuba roots 
quassia, etc., seemed to be fatal only to the very young cater- 
pillars and not always to those. The moths being entirely day 
flyers cannot be attracted by light and an attempt to attract 
them with a powerful kerosine lamp ended in a catastrophe fatal 
to four persons. 
. Handpicking and shaking the trees so as to dislodge the cater- 
pillars and eggs seemed the most effectual and economical 
method, but in cases like the present it should be begun on the 
appearance of the pest and kept up till all danger is over. The 
chrysalides should be collected f om their hiding places in rotten 
wood and dead leaves, etc., and where they can usually be found 
crowded together, as the caterpillars do not go far fro them 
bushes to pupate. 
Notes on the Bee-Hawk Moth Caterpillars. 
{Cephonodes Hylas). By A. L. Butler. 
I visited Petaling Estate on January 31st. There were then 
millions of the caterpillars busy at their work of devastation 
almost all were full-grown or of medium size, and I saw no eggs 
or very small young ones. Not a single moth was to be observed 
on the wing. The part of the estate worst attacked was on the 
