NOVEMBEB 16, 1906.] 



SCIENCE. 



625 



degree and to the effect that it tends to cause 

 an irregular transverse blotch (plainly formed 

 by the fusion of two original separate blotches 

 or spots) to appear in place of a transversal 

 pair of blotches. As to the first assumption, 

 the fact that the forming of the color pattern 

 of the beetle requires but an hour or so, that 

 it is carried on underground in the pupal cell, 

 and that it is at no time exposed to above- 



ffiMi m u^n mri,[ TpsgeigB^^ 



Fig. 4. Frequency polygon of the variation in 

 elytral pattern of 905 specimens of the Cali- 

 fornia flower beetle, Diairotica soror, collected 

 on the Stanford University campus, October, 1902. 



ground conditions until it is in definitive un- 

 changeable condition, and further that experi- 

 ments with related species of Chrysomelid 

 beetles (unfortunately not with this particular 

 ■one) in the way of submitting the pupa and 

 just-issued pattern-forming adult to various 

 different conditions of light, temperature, 

 humidity and color-surroundings, failed to 

 produce any positive results whatever; all 



these facts strongly tend to invalidate the as- 

 sumption of an ontogenetic determination of 

 the color pattern. The second assumption, 

 that of a change in environment in ten years 

 sufficient to produce consistent ontogenetic 



Fig. 5. Frequency polygon of the variation in 

 elytral pattern of 1,546 specimens of the Cali- 

 fornia flower beetle, Diairotica soror, collected 

 on the Stanford University campus, October, 1904. 



changes in the color-pattern, certainly does 

 violence to our knowledge, as far as it goes, of 

 meteorological, cultural and other life-influ- 

 encing conditions on our campus. No such 

 changes are apparent. 



The second explanation, that of natural 



