808 
THE TROPICAL AGRICULTURIST. [June 1, 1901. 
Life History. — Though we have a knowledge 
of tlic different stages ot the insect, from Uip 
to tlie adult, the full lite-history ia t'oi a'-.ouiatciy 
known. The eggs are laid either .siiifclj' o" in 
groups of from two or five, in tlie rind of the 
j3od (in the chs<i. of cacao), and in the yonn^c 
stalks (in the ease of tea). In the laitt-r tliey 
are almost invariably deposited at some point 
above tur " initial " or " fish " leaf. They are 
enioediled in the tissues of the plant, the only 
external indication being the presence of a pair 
of silvery hair-like horns projecting from the ex- 
tremity of each egg. fn ten days' time the egg 
hatches out into a small reddish insect, wiih 
longish legs and antennae, looking not ualike one 
of the slender ants that frequent the tea blossoms. 
This insect grows rapidly in size, without greatly 
altering in form, until it is nearing the firiiil 
change when small rudimentary wings may be 
observed sprouting from the sides of the body. 
In the course of its growth it changes its skin 
some three or more times (the exact numbRr has 
not yet been determined), and, after the last 
change, appears in the red, black, and white grub 
of the adult Helopeltis. In all its stages the 
insect maybe readily recognized by the so-called 
" drum-stick," or erect-knobbed horn projecting 
from the middle of the back (technically from 
the part called the scutellum). We do not yet 
know how many moults occur during the growth 
of the insect, the duration of these immature 
stages, or the length of life of the adult insect. 
The young insects do not thrive in captivity, 
and i have never been able to rear one up from 
the egg to the adult. 
Nothing is known of the natural enemies of the 
Helopeltis, if it has any. Should any insect or 
other animal be noticed attacking the Helopeltis, 
I should be greatly obliged if the observer would 
send me particulars of the fact, and, if possible, 
specimens of the assailant. 
Habits. — The Helopeltis insect feeds — in all 
its stages — upon the sap of the young leaves and 
shoots (or, in the case of cacao, upon the fruit). 
The symptoms are almost too well known to 
require description. Each puncture of the insect 
is followed by a dark brown or black spot, the 
tissues of the leaf being actually killed at that 
spot, partly by the exhaustion of the contents 
of the cells, and ])artly (probably) by the in- 
jection of some irritating fluid, though this has 
not been actually demonstrated. When the punc- 
tures are close together the spots coalesce, and 
the whole leaf shrivels and dries up. When a 
young bud is punctured, that bud dies back. 
When the insects are very numerous, every sin- 
gle bud may be killed back in this way, resulting 
in a complete cessation of flush. 
The insects feed at night and during the early 
hours of the morning. After 9 a.m. it is often 
difficult to find a specimen at work. It is still 
somewhat of a mystery where they conceal them- 
selves. It was thought at one time that the 
adult insects flew away to the jungle during 
the heat of the day, or retired into neighbouring 
shade trees. But this has never been proved, 
and is extremely doubtful. It is certain that the 
immature insects cannot remove themselves in 
this manner, and it has been observed that when 
disturbed tliese young insects run down the 
stems into the heart of the bush. It is most 
remarkable how, even in fields where they must 
be swarming, the Helopeltis insects secrete them- 
selve during the heat of the day. I have fre- 
qneitvly tried to shoke or heat them out of the 
tea Ku.^lii-s, bn-^ i'. is quite exceptional to secure 
a siiecimen in this way. A minute examination 
of the centre of the bush produces n > better 
rpouus, though it is almost certain that they are 
suniewhere there. It was thought possible that 
t'le insects mi(;ht go into hiding under stones 
and luo.se earth b'-low the bush. To test this 
tlieory, a broad baud of sticky substance (j;.k 
jaice was used) was applied to the stems of a 
certain number of trees at raiddaj'. All punc- 
tured leaves were plucked from these marked 
trees, but fresh punctures — evidently made hy 
immature insects— appeared during the following 
night, proving that they had been resting some- 
where above the sticky zone. Bunches of dry grass 
were placed in the centre of some bushes to see if 
the insects would hide in khem, but on pulling 
these to pieces later they w^ found to be unten- 
anted. 
The comparative immunity from attack of certain 
species or varieties of tea is most marked. Pure 
Assam indigenous is practically untouched. Of 
the hybrids, the more the plant partakes of the 
Indian strain, the greater is its immunity; the 
nearer the Cliina strain, the more is it open to 
attack. This fact was most conspicuous on an 
estate visited by me in Kahitar=i. Two adjoining 
blocks, without any intervening boundary, were 
planted, the one with Ai^fam indigenous plants, 
the other with alow jit hybrid. It was p"ssible 
to walk up between the two adjoining r>)ws and 
see the tea on one side quite healthy, while every 
bush CD the other hand was badly blighted. In 
another field of " indigenous " plants supplies of 
an infeiior hybrid had been put in. These supplies 
could be at once detected from a distance by their 
unhealthy blighted appearance. 
It is difficult to obtain careful records of attack 
— noted month by month — extending over several 
years. Bub I have one such record from an estate 
in the Kelani Valley, which gives the numbers of 
Helopeltis insects collected month by month dur- 
ing the last seven years, together with the monthly 
rainfall throughout that period. From these 
figures it appears that the worst attack takes 
place in July and August. After September there 
is a rapid drop, reaching its lowest level in Novem- 
ber, followed by a tendency to gradual (fluctuating) 
increase up till February or March, when there is 
another rapid fall. In April and May the pest 
practically disappears. The recrudescence com- 
mences towards the end of June and reaches its 
height in July or August. There thus appear to 
to be two periods of increase and decrease during 
the year, a major and a minor period. The major 
period is represented by the zero point in April 
and May, followed by the maximum in July and 
August. The minor period consists of the fall in 
September, October, and November, followed by 
the increase up to March. The March attack 
never approaehes the gigantic proportions of the 
July-August attack, the figures being approxi- 
mately as 4 to 9. 
The results obtainable from a sttidy of the rain- 
fall are rather conflicting. December, January, 
February, and March, during which time the 
pest is on the increase, are comparatively dry 
months and register tlie lowest rainfall. April, 
May, and June are very wet, and there is then 
scarcely any attack. Studying this period alone, 
one would be led to the supposition that dry 
