INSECTS AND DISEASES. 77 



the leaves. They cause the foliage to assume a 

 yellow tinge, and will soon make sickly the plant 

 they infest. A few applications of whale-oil 

 soap dissolved in warm soft water will often 

 destroy them ; this can be applied with a syringe, 

 taking care to throw the water upward to reach 

 the leaves affected, late in the afternoon, and 

 then washed off with pure water the following 

 morning. This insect does not attack plants that 

 are syringed with water daily, and all plants 

 grown under glass, not in flower, should be 

 sprayed regularly. When a house that has been 

 infested with Red Spider can be emptied of the 

 plants, it is well to burn sulphur on charcoal em- 

 bers ; the fumes from the sulphur are fatal to 

 nearly all insect life, and a house can by this 

 means be soon freed from this insect ; as burn- 

 ing sulphur is also destructive to plant life, this 

 process can only be used in emptied houses, un- 

 less only a slight quantity be used at a time. 



Rose Hopper, or Thrips (Tettigonia Bosce, of 

 Harris). — This is perhaps the most troublesome 

 pest with which the rose is afflicted in the open 

 air. It is a small, yellowish-white insect, about 

 three-twentieths of an inch long, with transpar- 



