446 
THE TROPICAL AGRICULTURIST. 
[Jan 1, 1901. 
five weeka after pruning) I found it covered with 
a minute form of the same insect. Under the lens 
it showed the same shape, colour, &c., as the orif;inal 
insect, and here and there it grew to nearly full 
size after some days. I stripped all the young flush 
off for about four rounds, and after that it again 
disappeared and I have not been troubled with it 
since. [This renewed attack after pruning can only 
be accounted for by supposing that a number of the 
cocoons had escaped observation at the time or 
pruning, being possibly concealed in the acgles of the 
stems and branches. These may have emerged as 
moths in three weeks' time and, failing leaves for 
the purpose, laid their eggs on the bark of the pruned 
trees. The eggs would have hatched out in about 
10 days, when the young larvse would commence 
feeding on the new flush. It is doubtful if they 
would have thriven under these conditions, as these 
caterpillars usually prefer the more mature leaves 
and avoid the young flush. — B, E. G.] I cannot find 
out anything about its propagation, which has 
puzzled me completely. I could find no trace of 
the moth ; but on all the trees attacked small round 
cocoons, black, about the size of a pea, with a smooth 
bark. like shell and a neat little trap-door at the top. 
were deposited thickly where the branches forked, 
1 was astonished to find that whereas at first in- 
sects about half or three-quarters size emerged 
from these shells, later on a considerable proportion 
of them hatched out a grub like winged insect, 
something like a white ant, but with small wings. 
I found, moreover, that as the full-sized insects 
died they shrivelled up, and in many cases I found 
small white lice-like insects clinging to the carcasses. 
I am inclined to think it was from these that the 
very small grubs which attacked my young flush 
came." 
There must have been some error of observation 
■here. The insect develops in quite the normal way, 
from egg to caterpillar, caterpillar to chrysalis (en- 
closed in its cocoon), and tiually chrysalis to winged 
"moth. It is possible that some confusion may have 
arisen from cocoons having been broken open, when 
the caterpillar, reduced in size, would be observed 
:awaiting its transformation into the chrysalis stage. 
•I cannot explain the '' grub-like winged insects," 
nnless they could have been the newly-hatched 
moths, before their wings had properly expanded. 
Tha '' white lice-like insects " were undoubtedly mites, 
which quickly swarm upon such dead matter, and 
could, of course, have had no connection with the 
subsequent brood of small caterpillars. 
Before this outbreak could have assumed the 
proportions described in the above correspondence, 
there must have been at least two earlier and smaller 
..broods. I can only repeat my warning — to keep a 
good look-out for these preliminary broods, and des- 
troy them before they have had time to gain ground. 
■When the pest is at its height, if the attacked 
field is nearing the proper time, pruning will be the 
best remedy, care being taken to effectually destroy 
all the prunings, and to search for and remove all 
cocoons attached to the stems of the trees. If the 
field is only just coming into bearing, the foliage 
may be thoroughly sprayed with arsenate of lead or 
some similar insecticide, which will poison the leaves 
and the caterpillars feeding upon them. No leaf 
should be plucked from such trees for at least 14 
days. The actual leaves that will then be taken 
will have been disclosed since the application of the 
poison, 
No. 6.— The Gkeen Nettle-gbub," Thosea cana 
Wlk. 
The caterpillar of this moth is practically indis- 
tinguishable either in form or colour from that of 
Thosea recta described above. It is perhaps more 
nsually without the red patches on the back, but 
this character is very variable in both species. The 
two insects have similar habits and appear to be 
eq[ually destructive. 
The moth of T. cana may be distinguished by its 
more uniform grayish-biown colour and by the 
absence of the short white-streak which marks the 
fore-wing of T. recta. T. carta has two indistinct brow- 
nish lines acoross the wing, with a small brown 
speck in the space between them' 
I have recently received specimens from the Kelani 
Valley district, where the pest appears to have been 
prevalent for Uiore than a year, and to have steadily 
increased its area of attack in spite of persistent 
attempts to check it by handpicking. My corre- 
spondent wrote as follows in March of the present 
year r — 
"The insect is just now present in great numbers 
I am catching as many as 2,000 per cooly. It attacks 
the same field every time, a somewhat poor jat of 
tea, appearing— as far ap I can make out— about 
every two or three mouths. Sick and small bushes 
are quite denuded of leaves. On healthy trees the 
leaves are almost eaten through, a thin skin only 
being left on upper side of leaf. [This is the work 
of the quite young caterpillars. The older insects 
will eat right through the leaf.— E.E.G].) This in- 
SRct appears to me to change colour as it grows, being 
at first green with yellow with a somewhat trans- 
parent appearance. [This is just before pupation.— 
E.B. G.] I can find no cocoons, nor any eggs ; the 
insect seems to come all at once. [The eggs would 
be extremely difficult to detect. The cocoons are 
probably attached to the stems.— E. E.G.] Healthy 
indigenous tea adjoining the fields attacked has so 
far escaped, with the exception of a very few indivi- 
dual trees. For the past three weeks we have had 
a most severe drought, and this attack is, I think, 
the worst I have experienced. A portion has just 
been cut across and allowed to run up again. Out 
of an area of 035 acres, all in one block, two fields 
only, one of 100 acres (2i years) and another of 100 
acres (I I year), are attacked. A field in which the 
insect first appeared is now quite free." 
An examination of particulars of rainfall supplied 
by the same correspondent for the year 1899 seems 
to show that the pest was at its height during the 
S,W. monsoon. April, with 20-35 inches ; May, 27-55 • 
June, 21-52; July, 10-72; and August, 5-47, are brao- 
ketted together with the remark that the caterpillars 
were very numerous over 80 acres, and that the collect- 
ing coolies were bringing in from 1,000 to 1,200 in- 
sects apiece. In September, October, and November, 
though a larger area was involved, the caterpillars 
are reported as being " not nearly so numerous." 
In the above case large numbers of coolies have 
been employed in collecting and destroying the cater- 
pillars, but apparently with little success in check, 
ing the attack. The fact is, that when once the 
pest has attained such vast proportions, it is almost 
impossible to eradicate it by artificial means. One- 
hundredth part of the same energy applied at the 
time of the earliest broods would have been much 
more effective. In young tei, such as the above, 
which is not in plucking, spraying with some arsenical 
compound could be freely employed without any 
possible danger. 
No. 7.— The " Feinged Nettle-geub,'' Natada 
nararia, Moore, 
Egg ; very in conspicuous, oval, flattened scarcely 
raised above surface of leaf, very pale green 
transparent, showing the colour of the leaf through 
it. They are laid singly on the upper surface of a 
tea leaf, andean only be distinguished by holding the 
leaf at an angle, when the surface of the eggs shine 
with a metallic iridescence. 
Caterpillar; varying in colour, pale green, yellowish 
green, or whitish green, often with a broad reddish 
brown or purplish stripe on the back, which is con- 
stricted or interrupted at a point near the middle 
and again near the hinder extremitv. This dorsal 
stripe has usually a darker outline of the same tint- 
All round the margin is a fringe of long pointed 
tubercles bearing tufts of stinging spines, and a row 
of smaller spiniferous tubercles on each side of the 
