REACTIONS OF ARTHROPODS TO LIGHTS 471 



spiders; Perez ('94) and Bethe ('98) on bees; and Fielde ('02) 

 on ants. 



Graber ('83, '84) made an exhaustive series of experiments 

 upon fifty- three different species of animals. Among the arthro- 

 pods used for these tests twenty-seven were insects and two were 

 spiders. Graber also attacked the problem from a ps3^chological 

 point of view in an effort to determine whether the lower animals 

 are able to distinguish colors and intensity differences. He studied 

 the distribution of the animals in an apparatus of two compart- 

 ments illuminated by lights of different colors. Graber used 

 screens to obtain his colored lights. From the results of his 

 large number of experiments he reached the following general 

 conclusion — ''dass die leukophilen oder weissholden Tiere mit 

 geringen Ausnahmen alle blauliebend, die leukophoben oder 

 dunkelholden hingegen rotliebend sind" ('84, p. 245). 



Graber also experimented on blinded cockroaches in an effort 

 to ascertain whether .these insects are able to perceive colors 

 and intensities through their chitinous integument. He blinded 

 the cockroaches by covering the surface of their heads with a 

 layer of warm black w^ax about 3 mm. thick and found when 

 red and blue screens were used the greater numbers still congre- 

 gated on the side of the apparatus illuminated with red. Graber 

 concludes from this experiment — ^'dass die geblendeten Kiichen- 

 schaben auch farbenempfindlich resp. blauscheu sind" ('84, p. 307). 



Gratacap ('83) in a short paper discusses some experiments 

 made, in the open at night, upon the responses of nocturnal 

 Lepidoptera. He placed colored tissue-paper cylinders over kero- 

 sene lamps and found the moths exhibited no marked 'prefer- 

 ence' for one color over any other. More moths were attracted 

 to the white light than to the colored lights, probably because 

 the light transmitted by the white paper was of greater intensity. 



Loeb ('90, '93, '05) studied the reactions of animals to colored 

 lights from the standpoint of the effectiveness of the different 

 rays in orienting the organisms. He objected to the application 

 of the expressions used by the so-called 'anthropomorphists' that 

 animals 'love' or 'prefer' certain colors and 'hate' or 'dislike' 



