159 
ON SOME ANIMAL PESTS OF THE HEVEA RUBBER TREE. 
By E. Ernest Green, F.E.S., F.Z.S., 
Late Government Entomologist, Ceylon. 
[ApstTract. ] 
The paper describes such animal pests of Hevea as have 
come under the writer’s personal observation in Ceylon, and 
briefly notices other pests of the plant that have been recorded 
by various observers in other countries. 
Such records are remarkably few, and it may be assumed that 
the Hevea tree is still exempt from any serious or widely spread 
animal pests. 
This comparative immunity may be due partly to the pro- 
tective nature of the viscid latex that exudes profusely when a 
healthy tree is wounded, and partly to the small number of 
years during which the plant has been under cultivation. 
Where possible, recognized methods of control have been 
indicated. 
[Drscusston. ] 
Mr. G. Starrorp Wuitsy: Mr. Chairman and Gentlemen— 
With reference to the author’s remarks on the function of 
latex, which is of particular interest to. myself, I am very much 
inclined to agree with his position that one, at least, of the 
functions of latex is that it serves as a protective agent against 
the attacks of insects. In that connection I might draw atten- 
tion to one fact which is not generally appreciated, and that is 
that the latex, as we are acquainted with it on the estates— 
that is, latex obtained from the trees by regular tapping after 
wound response has set in—is very different in its tendency to 
coagulate from the latex which exudes when a Hevea tree is 
first punctured. In the latter case the latex coagulates almost 
instantaneously, but afterwards the latex may, and in fact 
does, remain in a liquid condition for several hours; and it 
is the latex present in the tree before any tapping has gone on 
that we have to consider in respect of the function of latex in 
regard to insect defence. Of course, I do not think that is 
the prime function of latex, but I certainly think it is a 
function. I was given a very interesting instance on that 
point some time ago by a planter who found that some of the 
tobacco pests got on to his rubber trees, but they were never 
able to get inside. They were always stuck there as soon 
as they had made an incision; the latex exuded, and coagulated, 
and kept them there. There is one other point I might perhaps 
