REACTIONS OF ARTHROPODS TO LIGHTS 



503 



3. Results. Single monochromatic lights were used first to 

 determine the relative effectiveness of each light in stimulating 

 the cockroach. The direction of the lights was reversed with 

 each ten trials, but for a matter of convenience the records are 

 combined. 



From the records of the experiments shown in table 11 it may 

 be inferred that the cockroach is positive to blue, negative to 

 green and yellow and indifferent to red, results which are borne 

 out by experiments with balanced lights of different colors to 

 be described later. 



When paired lights of the same colors were used, there was 

 practically an equal distribution of responses to the two sides. 



The records in table 12 while of no value in determining the 

 relative potency of the colors, do show the degree of reliability 

 that can be placed on tests of cockroaches with balanced pairs 

 of lights. 



TABLE 11 

 Reactions of Periplaneta to single monochromatic lights 



TABLE 12 



Reactions of Periplaneta to pairs of monochromatic lights of the same quality and 



of equal intensity 



