302 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 4 



usually blows to have any effect on the scales on the tree, but once 

 dislodged the wind might carry them to an adjoining tree if the foliage 

 of the different trees were in close proximity. 



Rate of Travel Over Smooth Paper 



In order to determine the maximum distance that young scale 

 insects would travel under the most favorable conditions, accurate 

 records were made of the movement of the insects over smooth paper 

 for two-hour periods. Tracings representing their actual movements 

 were made on large sheets of paper and will be reproduced in a later 

 publication. Tabulation of the data is given in the accompanying 

 table. It will be seen that temperature has a very great influence 

 on the activity of the insects. The minimum temperature of 73.5° F. 

 on which records were made for the black scale shows a maximum 

 distance traveled of 81 inches with an average of 71.5 inches, while 

 with a temperature of 90° F. the maximum distance traveled was 

 180 inches with an average of 151 1-3 inches. It thus appears that 

 .an active young black scale will travel more than twice as far upon 

 .a raise in temperature from 70° to 90° F. 



The influence of temperature is similarly shown in the case of the 

 red scale. At a temperature of 66° the maximum distance traveled 

 was 41 inches, while with a temperature of 91° the maximum distance 



RATE OF TRAVEL OVER SMOOTH PAPER 

 Black Scale {Saisietia olece Bern.) 



