474 ALFRED O. GROSS 



losen die Kurven der relativen Reizwerte der verschiedenen 

 homogenen Lichter annaherend oder ganz ubereinstimmen mit 

 der Helligkeitskurve fiir den total farbenblinden Menschen bei 

 jeder Lichtstarke und fiir den dunkel adaptierten normalen 

 Menschen bei entsprechend lichtschwachem Reizlichte." 



In this brief re\dew of the Uterature pertaining to the reactions 

 of the lower crustaceans and insects to colored lights, we find 

 a great diversity of results and opinions, Merejkowsky ('81) 

 maintains that the difference in response exhibited by the ani- 

 mals to the different regions of the spectrum is due not to the 

 quality of the light but to the relative intensity of the colors. 

 Hess ('10) believes that the relative attractive power for the 

 different colors approach or correspond with the brightness curve 

 of the totally color-blind persons. Gratacap ('83), Plateau ('97, 

 '99), Bulman ('99) and Bonnier ('79) believe that insects are 

 not guided in their movements by color, and Yerkes ('99) states 

 that the factor of intensity has the more important role in the 

 aggregation of Simocephalus in the yellow and red regions of 

 the spectrum. On the other hand Bert ('68), Lubbock ('79, '81, 

 '81a, '83, '04), Graber ('83, '84), Loeb ('90, '93) and others 

 believe that the lower animals perceive or are stimulated by the 

 different colors as such. With the exception of the work on 

 Simocephalus, about which there seems to be much difference 

 of opinion, the results of these investigators in general support 

 the conclusion that the blue or the more refrangible rays of the 

 spectrum are most effective in producing a response in the ani- 

 mals which they tested. It is apparent from the work thus far 

 done that it is extremely doubtful just what part the intensity 

 and what part quality of the light has in stimulating the organ- 

 ism. The great variations in results and the conflicting opinions 

 concerning the relative efficiency of the colors is doubtless due 

 to the fact that in none of these experiments was the intensity 

 factor eliminated. Furthermore the lights used in many of the 

 experiments were produced by means of screens which have been 

 shown to be unreliable. 



It is the purpose of this paper to present the results of inves- 

 tigations on the reactions of some of the lower animals to spec- 



