196 WILLIAM BRODBECK HERMS 



EXPLANATION OF FIGURES 3 TO 10 



3 Calliphora vomitoria. Course of a larva with light of differing intensity from 

 opposite sides. 



4 Lucilia caesar. Course of a larva with light from two directions, and 

 differing in intensity. 



5 Calliphora vomitoria. Course of a larva with balanced light on opposite 

 sides. 



6 Calliphora vomitoria. Behavior of larvae in non-directive graded light, 

 under a directive intensity of about 50 CM. 



7 Calliphora vomitoria. Behavior of larvae to graded non-directive light, 

 after having previously been in the dark. Note the strong deflection of the 

 path due to the after effects. 



8 Lucilia caesar. Behavior of larvae to graded light while under the influence 

 of a weak directive stimulus (about 0.5 CM.) 



9 Lucilia caesar. Movements of the larvae when forced into the negative 

 end of a field of light grading at the rate of 7 C M. per cm. There was a con- 

 tinuous directive intensity of about 0.5 C M. 



10 Lucilia caesar. Movements of a larva when forced into the negative end 

 of a field of light grading at the rate of 35 C M. per cm. There was a continuous 

 directive intensity of about 0.5 CM. 



