: PART IV. 
young plantation, it will usually be found that vhe leeward side of the 
trees is the worse affected, and those trees which have been so grown 
that the lower primaries are bunched thickly together and touching 
the ground. 
There are therefore two means at our disposal of helping the 
climate to control the Mealy-bug; firstly the avoidance of wind-breaks 
to ensure a free circulation of air through the plantation, and secondly 
a system of pruning that will avoid numerous primaries touching the 
ground, thus maintaining a good circulation of air in the tree itself, 
especially round its base. The rigorous suppression of weeds will also 
help to keep the relative humidity at a lower figure. 
These recommendations are naturally only made from the point 
of view of controlling the mealy-bug, though they will also assist in 
the control of several other insect pests of coffee in this country. It 
is realised that in parts of the country wind-breaks may be essential, 
although in those districts where mealy-bug attack is most prevalent, 
they do not appear to be so, at any rate after the coffee has become 
well established. The suggested elimination of the lowest primaries 
has however, in the opinion of the Senior Coffee Officer and of the 
Mycologist, several other advantages, apart from the question of insect 
pests. 
As regards the destruction of alternative food supplies, it is 
possible that not very much can be accomplished in this direction. 
Theoretically, a belt at least fifty yards wide should be cleared at the 
edges of a coffee plantation, and if possible not planted with any crops 
at all, but at any rate not .with a crop that can be a host of mealy-bug 
or any other coffee pest. This will minimise the risk of infection being 
carried to the coffee by man or animals; but nothing can eliminate the 
risk of wind-borne infection; and the principal cause of mealy-bug 
suddenly appearing in a hitherto uninfected locality is wind—especially 
‘“ dust-devils ’ which may pick up leaves and carry them long 
distances. 
Thirdly, the utilisation of indigenous parasites. Only one internal 
parasite of the common coffee mealy-bug has so far been found in this 
country, and that appears to be exceedingly rare, so that it has not 
been possible to obtain enough to breed them. Two mealy-bugs, both 
of them closely related to that on coffee, have been found on two 
species of wild plants, and both these mealy-bugs are heavily 
parasitised by two different species of Hymenoptera. Unfortunately, 
neither of these parasites can be induced to attack the coffee mealy- 
bug: indeed, were they capable of it, they would probably have done 
so long ago without any artificial aid. 
Practically nothing therefore can be expected from parasites, but 
in the utilisation of the predatory enemies of the mealy-bug lies the 
chief hope of combating this pest. 
There are already known to exist in this country nearly forty 
different species of insects which feed on the coffee mealy-bug. 
Though some of these are scarce and of little practical importance, it 
will be of interest to give the full list. 
ORDER Psocoptera. 
About nine species of these small insects are known to prey on the 
coffee mealy-bug; only one of which, the commonest, has so far been 
named—Ectopsocus briggsi, Mel. This is mainly a dry-weather insect 
190)