ANIMALS INJURIOUS TO FRUIT TREES. IQ 



scale insects. At the time of its publication I was carrying out 

 experiments myself on the subject, and as some of these confirm Mr. 

 Quayle's conclusions, and other interesting facts have been brought 

 out, of economic importance, they are described here in detail. 



The species experimented with was the White Woolly Currant 

 Scale (Pulvinaria vitis var. ribesiae, Sign.). The life-history is well 

 known, having been described in various works on economic 

 entomology, and need not be entered into here. 



My first experiment was made by placing six newly-hatched scales 

 on three separate sheets of smooth white paper, each measuring 

 72 x 42 inches. Previous experiments had shown that the scales 

 invariably travelled towards the light, the papers were therefore 

 placed on the laboratory bench facing the window, in a temperature 

 of 78 F. The young scales were placed at the side of the paper 

 furtherest from the light, and the distance travelled was marked off 

 each half hour for two hours, and then carefully measured. 



The second experiment was a repetition of the first in a tempera- 

 ture of 82, and a third was tried in 84. 



The results are tabulated below. 



RATE OF TRAVEL ON SMOOTH PAPER. 



A further series of experiments were made, using a sheet of glass 

 instead of the smooth paper. As the results were practically the same 

 as those tabulated above, the actual figures are unnecessary. 



Finally, three series in different temperatures were made on the 



