7i 



by white-washing with lime and water. This requires renewal once 

 in three weeks. Special preparations are sold for applying to trees. 

 In the form greasy mixtures, rosin and castor oil, whale oil-soap 

 and washing soda, soft soap and carbolic acid are recommended 

 for this purpose, but these must not be allowed to remain long on 

 the trees. After 2 to 3 months, at most, they should be washed 

 off. Trunks of valuable trees can be protected by tying tarred 

 paper, or newspapers, around them, or by fixing wire netting one 

 inch away from the bark closed at the top and bottom. Lime, 

 ashes and soot can often be employed very usefully in gardens, 

 especially against snails and slugs. 



Stored crops are very liable to the attacks of insects. Grain may 

 be freed from weevils by exposing it for 24 hours in an airtight 

 receptacle, to the fumes of carbon bisulphide at the rate of I 

 teaspoonful (1 drachm) per cubic foot of space. This will kill 

 every insect within 24 hours and will not damage the yrain. Car- 

 bon bisulphide is obtainable in cans from 7 lbs. upwards at about 

 $d. per lb. in England or the United States. Benzene may be 

 used in the same way, taking rather more per cubic foot as it is 

 less powerful. As both these substances are very inflammable, 

 care must be exercised in using them. Cockroaches can be des- 

 troyed by mixing equal parts of molasses, or chocolate, and boracic 

 acid, and spreading this on small pieces of tin or cardboard, which 

 are placed in cupboards or under furniture. The mixture is not 

 poisonous to dogs and other domestic animals, but will destroy the 

 cockroaches. Books in the tropics should always be lightly painted 

 over with the following mixture to preserve them from cockroa- 

 ches : — 



1 oz. Corrosive Sublimate. 



1 oz. Carbolic acid. 



2 pints Methylated or Rum spirits. 



The paste use for binding books and similar work should be 

 poisoned by adding half an ounce of copper sulphate (blue stone) 

 to every pound of paste. 



Wicker and other furniture attacked by small beetles should be 

 thoroughly painted with kerosene oil and then placed in the sun 

 for a few days. Woollen good-, clothes, etc., can be preserved 

 from the clothes' moth bv the use of naphthalene, but better by 

 being thoroughly sunned for a whole day once every two months. 



Useful Insects. 



Insect pests, like other organisms, have enemies that prey on 

 them clearly, these are of value and deserve to be encouraged. A 

 common pest destroyer is a green fly about an inch long with large 

 transparent wings, and beautiful golden eyes, which emits a very 

 unpleasant smell. Its eggs are found on the bark or leaves of 

 plants infested with plant-lice, and are easily recognizable, resemb- 

 ling small white grains on a slender stalk. The grub is a very 

 voracious animal and devours large numbers of plant lice, etc. 

 Other useful insects are the small round beetles known as ladybirds, 

 fhi ir grubs are usually coloured black and yellow, and are very 



