18 



Kerosene emulsion, made by the same companies, costs from 12 to 15 

 cents a gallon. In using these oil emulsions it is advisable to first 

 break the water by the addition of a little lye, one-fourth pound being 

 ample for 50 gallons of water. 



Kerosene emulsion. — This wash, made according to the old formula 

 (kerosene, 2 gallons; whale-oil soap, one-half pound; water, 1 gallon), 

 is prepared in the same way as the distillate and used at the same 

 strength. It does no harm to use double the quantity of soap indi- 

 cated, securing in this manner a rather more stable emulsion. This 

 emulsion, while perhaps somewhat less eflicient than the distillate 

 emulsion, is always available where the latter may not be in reach. 

 It may be prepared on a small scale with an ordinary hand pump, but 

 is best prepared in large quantities with a gasoline or steam-power 

 pump to mix and emulsify it after the soap has been dissolved in the 

 water by boiling. 



The resin wash. — This wash is especialh^ valuable against the Cali- 

 fornia red scale. It may also be used against any other scale insect, 

 including the black scale and the various armored scales affecting citrus 

 trees. The wash is made as follows: Resin, 20 pounds; caustic soda 

 (78 per cent), 5 pounds; fish oil, 2^ pints; water to make 100 gallons. 

 Ordinary commercial resin is used and the caustic soda is that put up 

 for soap establishments in 200-pound drums. Smaller quantities may 

 be obtained at soap factories, or the granulated caustic soda may be 

 used, 3^ pounds of the latter being the equivalent of 5 pounds of the 

 former. Place these substances with the oil in a kettle with water to 

 cover them to a depth of 3 or 4 inches. Boil about two hours, mak- 

 ing occasional additions of water, or until the compound resembles 

 very strong black coffee. Dilute to three times the final bulk with hot 

 water, or with cold water added slowly over the fire, making a stock 

 mixture to be diluted to the full extent as used. When sprayed the 

 mixture should be perfectly fluid, and should an}' sediment appear 

 the stock mixture should be reheated; in fact, the wash is preferably 

 applied hot. This wash is more difficult to prepare than the emulsions 

 referred to above, and is therefore much less employed. 



CITRUS SCALE INSECTS: CLASSIFICATION AND CHARACTERISTICS. 



For the purpose of this paper a ver}^ simple classification of citrus 

 scale insects may be adopted, nameh': (1) The armored scales, or those 

 forming a protective covering scale and losing their limbs and the 

 power of changing their situation as soon as they settle down to feed 

 as newly hatched larvce; (2) those species which secrete no covering 

 shell or scale and retain their limbs and the power of moving about 

 during most of their lives. 



The species belonging to both groups are commonlv called scale 

 insects, although the term might seem properly to applv only to the 



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