292 
THE TROPICAL 
AGRICULTURIST. fNov> r. 1894. 
these insect pests, but did not complete the life USetory 
ot either. The question as to the duration of Mos- 
quito life he does not even touch upon. Jiut he showed 
that the eggs were deposited on the young twiys : that 
the respiratory processes of the newly laid eggs so 
closely resembles the fine pubescence Wnicb clothes t la- 
surface of the shoots as to be quite indistinguishable 
froul it to the unaided eye : that the knobbed ends 
and also the sides of the two tubular processes of 
the mouth of the egg-shell, to a greator or less ex- 
tent, arc studded with button-shaped elevations, each 
of which has a minute pit in bis centre; that those 
pits arc probably the ends of minute tubes which 
place the lumens of the processes in direct communica- 
tion with the exterior, ami thus serve to carry air 
to the developing ovum: that the eggs are provided 
with deep saucer-shaped lids, perforated sieve. like, 
with boles which are large enough to admit sper- 
matozoa. 
These and one or two more of Mr. Wood-Mason'* 
observations, 1 venture to think, are of much practical 
value. By thoroughly saturating the young twin's, it 
may be possible to cause the insecticide to penetrate 
through the respiratory tubes and thus destroy the 
embryos. 
But if attention be directed to the destruction of 
the embryo, it should not be forgotten, as pointed 
out by Mr. Wood-Mason, that the females instinctively 
avoid puncturing the shoots or parts of the shoots in 
which they have laid their eggs, for, says Mr. Wood- 
Mason, "one can rarely find c;rg* on badly injured 
shoots." A thorough syringing of affected bushes, more 
especially of the sprouting buds of these (which to 
the casual observer may seem free from the pi Bl i 
would give full scope to the treatment. But in con- 
cluding this paragraph, I would caution you against 
the mistake made on more occasions than one, of 
regarding the eg£s as young insects; the two unequal 
processes which spring from the mouth of the egg 
have been regarded as the antennae of young (perfect) 
insects deposited in that State. 
7 But Mr. Wood Mason, in trying to account for 
the reported greater prevalence of the disease on the 
Chinese or hybrid Chinese stock of tea bushes, dwells 
on the fact that the descrimiuation manifested by many 
insect pests is doubtless due tp a high sense of Bincll 
possessed by these creatures. And I would add to his 
observations that it is well-known that fungoid pests 
aro remarkably good botanists. They choose not only 
uniformly the same hosts Upon which to live, bul may 
even frequent but one variety of the species. The 
practical value of these observations may lie in the 
fact that without poisoning the Mosquito it is just 
possible the Auhatoda infusion may drive the insect 
away by its offensiveuess. If driven away and syste- 
matically kept from the tea plant, the effect would 
be the same to the planter as if poisoned. 
My experiments with the drug satisfied me beyond 
all doubt, however, that to certain forms of life it is 
a powerful poison, and I am therefore sanguine in 
my expectation that careful investigations will reveal 
the fact that it is an actual insecticide to Mosquito 
and other minute insect pests that frequent the tea 
and other plants, such as the green fly of the garden 
rose. But I wish it to be e'early understood that I 
hold that it requires to be demonstrated in each case 
whether or not Auhatoda possesses that property on 
the pests that may be in question. 
8. You do not appear to be troubled with the Tea 
mite. It would seem to me that Auhatoda might be 
even more energetic with that pest than with Mosquito, 
from the fact that the entire life of the mile is spent 
on the surface of the tea leaf. The eggs are laid in 
the recesses formed by the branching of the veins of 
the leaf, and the tapering extremities of . the eggs are 
directed upwards in such a manner that there should 
be no difficulty in killing their contained embryos. 
The youn,g arachnids leave the egg as 6-footed larvae, 
but they do not emigrate from the plant as voyagers 
on the backs of winged insects (as many other mites 
do), but attain to adult state by a change of skin.' 
It seems probable that the entire life of the Tea-mite 
is spent on the self-same leaf as it was born on, so 
(hat assuming that Adhatoda is a specific against this 
pest, its extermination should be comparatively easy 
matter. 
9. in a communication I have had tic- pleasure to 
receive from Messrs. Barry A Company, (dated fJnl 
July) a tea planter, furnishes certain particular!) re- 
garding "Green fly." "Jt lives,'' he says, " entirety 
on the lower side of the leaf and is not p-ot at so 
easily as mosquito or red spider, and i doubt it it 
could he syringed out in the samo way. It a|gp curls 
the Leaf downwards Oil all sides and so forms M hollow 
dome in which in it lives and breeds - This would also 
be the means of protecting it from the swinge. ' Tilers 
are doubtless many mechanical dinicul lies that would 
have to be got over, but these need not Ik- considered 
at present, What we have to discover in the first 
place is whether green fly, mosquito and red spider are 
killed by the iuaecticide fit not. To yourself and your 
enlightened brother planters, I trust may soon be due 
the credit of having brought the experiments «itU 
AnilAToDA to final and successful issue*. 
'iEo. Watt, 
flejJOrter on Economic Product* to the (joi*ernmrnt of India. 
"ADHATODA VASKA. 
Dear Sib,— The plant that Mr. Melville White has 
recently been writing about, is common in the Western 
Province, it is known to the Sinhalese bv no less 
than three names viz.: Af/aladara, H'ana kpala. and 
I'aicatta. It is used medicinally by the Sinhalese 
in the shape of decoctions for cough, but is a most 
nauseating drug. The dry leaves arc rolled into cigars 
or rilled into pipes ana smoked also for cough, 
similarly as the JJatttra (attana) leaves are for asthma. 
A fomentation of the leaves boiled ie greatly relied 
on for lumbago. That cattle, sheep and goats'will not 
eat the leaves is a fact, but whether it is an insecticide 
remains to be proved. C. A. C. 
THE NEW ALLEGED INSECTICIDE, 
• "ADHATODA/' 
We are disappointed to see by the in- 
teresting letter Mr. E. E. Green lias went U 
(see below) — that an experiment instituted by 
him with the new insecticide lias not been 
successful. Wo have given above the important 
portions of the letters of Dr. Geo. Watt 
and Mr. Mot an sent to the Chairman, P. A. 
Dr. Watt does not speak of distillation in 
the required infusion, but of a few leaves 
squeezed or broken into a glass jar with water 
clearing, in 4 or 5 hours, the said water of minute 
organisms which would be found not only killed, 
but more or less decomposed. Mr. Moran was 
successful in clearing some 20 patches of tea at- 
tacked by mosquito after 4 to 6 syringing* with 
an infusion from the leaves. 
"ADHATODA— AS AN INSECTICIDE; 
AN UNSCCCESSFUL EXPERIMENT. 
Eton, Pundaluoya, Oct. 29th. " 
Dear Sir, — I have noticed in the local papers 
some correspondence about a Ceylon plant— the 
'• Adhatoda " — which is said to possess insecticidal 
properties. I hope it will be thoroughly tested 
and that the statement may be corroborated. 
But a little experiment that I have just tried 
with this plant failed to prove anything of the 
sort, Dr. Trimen very kindly sent me a small 
piece of the "Adhatoda," from which I brewed 
a strong tea-coloured infusion. The quantity was 
insufficient for experiment in the field. But to 
test its qualities I immersed in the mixture several 
tea branches, infested with the tea aphis ( Gcyloma 
thececola), until both leaves and insects were 
thoroughly wetted, I then took them out and. 
