72 
active. They eat large numbers of plant lice, away from which it 
is rare to find them. 
Should other parasitic or predaceous insects be found, they 
should be preserved ; but as a rule it is not an easy matter to deter- 
mine those that are useful, without a special study of their habits. 
Introduction of Pests. 
It is a very easy matter to introduce injurious insects or plants 
from other localities and care should be taken to avoid doing this. 
A pest introduced into a new locality is likely to be more destruc- 
tive than those already established there. Cuttings, plants or seeds 
are very likely to carry the eggs of scale insects, or the scale insects 
themselves, and all importations should be examined on arrival. If 
possible, it is wise to plant such things by themselves so that any 
disease that may show itself will not readily spread and can be 
treated before the plants are put out with others. 
Sources of Danger. 
Badly diseased plants, if few in number, should be cut down and 
burnt, lest the disease spread to neighbouring plants. This is always 
necessary even with scale insects and me ily-bugs. A diseased 
plant should never be cut down and left lying on the ground. Any 
pest on it will spread to other plants on which the insects can live, 
since they will at once leave a plant when the sap ceases to flow. It 
is sometimes possible to discover the sources of insect pests. Some 
trees are continually attacked by scale insects and they communi- 
cate their pests to many others of various kinds. In Barbados, the 
Frangipani trees are very dangerous in this respect, having usually 
scale insects that will live on a great variety of other trees and 
shrubs. It would be of little use to treat the other trees and leave 
the Frangipani, as it would immediately communicate the disease 
afresh. Such dangerous trees should not be allowed to grow near 
fruit trees or valuable ornamental plants. 
Collecting and Forwarding Specimens. 
Injurious insects may be forwarded for examination to Director 
of Botanic Gardens, Singapore. They should in every case be so 
preserved and packed as to arrive in the best possible condition 
for examination. 
Flies, butterflies, moths, bees, etc. should be dried and, if possi- 
ble, either carefully pinned or at any rate prevented from rolling 
about and becoming injured. 
Soft-bodied insects such as caterpillars, grubs, “worms/* etc. are 
best preserved by being dipped in boiling water and then dropped 
into a small bottle of strong spirit or rum. They may also be 
placed in the spirit direct, which will be sufficient to preserve them. 
Beetles should be sent wrapped up in paper or in any other soft 
packing material, but no insect should be packed directly in cotton 
wool; a layer of paper should always be placed between the cotton 
wool and the insect. Scale insects are best preserved on the leaf 
or part of the plant they attack. Several leaves should be dried 
carefully, packed and forwarded in a box. It is often possible to 
