RELATIVE PHOTOTROPISM. 



359 



arrangement of the tests thus obtained, though not entirely 

 complete, were felt to be at least amply sufficient to avoid any 

 significant effect from such a source of error. The results 

 obtained by these methods are presented concretely in Table I., 

 and Graphs I., II., and III. 



TABLE I. 



WILD FLIES. 



VESTIGIAL FLIES. 



Tube Horizontal. 



Tube Vertical. 



1 These numbers are merely for convenience in designating, and do not indicate 

 that the tests were always given in this order (see text). 



