626 



SCIENCE. 



[N. S. Vol. XXIV. No. 620, 



selection, based on a rigid intra-specific or 

 individual selecting, tending to preserve the 

 middle-spots-fused condition at the expense 

 of the middle-spots-free condition, assumes an 

 actual visual discrimination — let alone a pre- 

 sumable esthetic or preferential one — on the 

 part of the lizards, birds and insect enemies 

 of Diahrotica; that is, to be flippant, coming 

 it much too strong for me. We really know 



Fig. 6. Frequency polygon of the variation in 

 elytral pattern of 1,000 specimens of the Cali- 

 fornia flower beetle, Diahrotica soror, collected 

 on the Stanford University campus, October, 1905. 



something about the eyesight of lizards, birds 

 and insects and it is fantastic to credit them 

 with a capacity for distinguishing a character 

 that in many cases requires on our part care- 

 ful scrutiny with a lens to make out. When 

 we straighten up after an hour's eye-straining 



work on this minute, though none the less 

 real and from the species-student's point of 

 view important, variation condition among 

 our hosts of beetle specimens, we have in our 

 minds one conviction about which there is 

 moral certainty, and that is that no lizard. 



Fig. 7. Frequency polygon of the variation in 

 elytral pattern of 1,120 specimens of the Cali- 

 fornia flower beetle, Diahrotica soror, collected 

 in the foothills of the Sierra Morena Mountains, 

 about three miles from the Stanford University 

 campus, October, 1905. 



