LIGHT REACTIONS METABOLISM MAY-FLY NYMPHS 433 



difference is of course negligible as is also the difference between 

 these acid-treated animals and the control. 



Alcohol was also effective in making these negative nymphs 

 positive. Fourteen nymphs that were made positive gave a 

 resistance of 91 ±7 minutes to the cyanide as compared with 

 130 ± 4 minutes for the sixty-one control animals. This is 3.5 

 times the probable error. The eleven nymphs that were treated 

 with alcohol and remained negative showed some stimulation 



TABLE 3 



Showing the sign of pholotactic reaction of Leptophlehia nymphs and their resistance 



to cyanide 



NUMBER 

 TESTED 



AVERAGE 

 LENGTH 



AVERAGE 

 SURVIVAL 



TIME 



TREATMENT BEFORE KILLING 



NUMBER 

 TESTED 



AVERAGE 

 LENGTH 



AVERAGE 

 SURVIVAL 



TIME 



Positive nymphs 



Negative nymphs 



when tested with cyanide, but not so much as the positive nymphs. 

 Considering the numbers tested and the small deviation from 

 the resistance shown by the control animals, none of the results 

 obtained with other reagents and listed in table 3 are significant 

 with the exception of those with chloretone. This drug was not 

 very efficient in causing reversals, but did cause decided de- 

 pression, as measured by the cyanide method, and caused re- 

 versals in about 30 per cent of the nymphs treated. 



