222 WILLIAM BRODBECK HERMS 



orange band when given the entire range of the spectrum. Sudden 

 increase or decrease in intensity, jarring, or changing Ughts sud- 

 denly, caused the larvae to abandon temporarily the positive 

 relation to light. 



4. The migrated larvae of Lucilia caesar are negative to 

 any color of the spectrum when the color is used singly, but they 

 will collect on the side away from the source of the light in the 

 yellow-orange band when the entire range of the spectrum is 

 available. The blue end of the spectrum is strongly avoided. 



5. The larvae of both species as individuals react negatively 

 to directive light throughout this stage, but are not strongly 

 responsive on hatching, becoming more and more markedly so 

 as they grow older. They are also strongly reactive to shadows, 

 i.e., are photopathic. 



6. The imagoes emerge from the pupal stage as organisms 

 positive to light. 



7. The lowest directive intensity to which the larvae of Lucilia 

 caesar respond is 0.00076 CM., while for Calliphora vomitoria it 

 is 0.007 CM. 



8. Below the respective minimum directive intensity, light 

 still has a dynamic effect until an intensity of 0.00007 CM. is 

 reached, when the conditions are equal to darkeness,z.e., the larvae 

 remain at rest. 



9. The courses of the larvae under stimulation from two 

 sides always lay more or less transverse to the light rays, the greater 

 deflection being toward the light of lower intensity regardless of 

 the size of the luminous field. 



10. When placed midway between two balanced lights of like 

 luminous areas (or unlike areas, but like intensity) their course 

 lay midway between the two lights, transverse to the direction 

 of the rays. 



11. There is no constant relation between the movements of 

 the larvae and a graded field of non-directive light. 



12. With a proportionately high directive intensity, the larvae 

 passed directly into and through a field of higher intensity (non- 

 directive), but when a proportionately low intensity was used the 



