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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 



