LIGHT REACTIONS METABOLISM — MAY-FLY NYMPHS 451 



TABLE 12 



Showing the effect of 2 per cent ethyl alcohol upon the phototactic reaction of nymphs 

 negative to light and upon their carbon dioxide production 



1 These control nymphs were more active than the experimental ones before 

 the biometer test was made. 



Chart 4 Showing the reactions of two positive nymphs to light after treat- 

 ment with N/25 hydrochloric acid together with their controls and the result of 

 treating three nymphs with 2 per cent ethyl alcohol with one control tracing. 

 The control shown in column 6 remained quietly at the negative end during almost 

 all of its exposure and yet gave more carbon dioxide than the more active alcohol 

 treated nymph whose response is shown in column 5. The nymph shown at the 

 bottom of column 1 became negative immediately upon treatment with the acid. 

 The experimental dish was then twice turned end for end each time the nymph 

 moved directly away from the light. 



