Sept., '02] ENTOMOLOGICAL NEWS. 225 



pliur prepared for this department for the dipping of sheep 

 under the provisions of the Sheep Scab Act. The analysis of 

 ten drums, including the one used from in the experiments, 

 showed the strength to be nearly uniform and the ratio of lime 

 to sulphur to be about 1:2. In test 5 the strength of the wash 

 in terms of the dissolved lime and sulphur was estimated to 

 approximate that of the ordinary lime-sulphur-salt wash, while 

 that used in test 6 was half this strength. It was desirable to 

 test the sheep dip because it is a reliable article, easily procur- 

 able at moderate cost and ready for dilution with water. 



Large bearing trees in consecutive rows of four trees each 

 were selected for treatment and six similar trees reserved for 

 "controls," making a total of thirty trees under observation. 



Duplicate tests were made on the farm of Mr. Henry Myers, 

 at Simondium, near Paarl, about 40 miles from Cape Town, 

 using a large number of trees under a great variety of condi- 

 tions, three series of four trees each being thoroughly drenched 

 with water one, two and three days after treatment with the 

 hope of getting some idea of the effect of a heavy rain soon 

 after spraying. 



Live scale and eggs were abundant on all of the trees, but 

 in some cases at least 50 per cent, of the scales, other than 

 those that had reproduced and died, were already dead, especi- 

 ally on the trunk and larger limbs — an unexplained fact often 

 observed during the winter season in regard to both Aspidiotus 

 aurantii Maskell and the species under consideration. 



The wash in each case was applied while hot. The lot that 

 was tested registered 155° F. in the tank. Six to eight inches 

 from the nozzle the spray registered 140° F.; about two feet 

 away, only warm ; farther away, cold. The advantage in keep- 

 ing the solution hot is due to the fact that the soluble com- 

 pounds .show a tendency to crystallize when cold, especially if 

 left .standing over night. In such case considerable boiling is 

 necessary to redi.s.solve the crystals, otherwise they are apt to 

 l)e left in the tank. Even though kept in suspen.sion by the 

 constant agitation of the mixture, the crystals will not only 

 lodge on the tree unevenly but will be more easily removed by 

 wind and rain. 



