36 



EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES. 



The variability in diameter of spot 1, shown in fig. 22, is a partial expla- 

 nation of the previous polygon. Here the variety caseyi and variety quin- 

 quesignata include these individuals at or near 15 units, while the typical 

 specimens are at or near 5 units. 



( " } 



('') 



(') i> 



(<() 



() Diameter of spot 1. 



(6) Males. 



(c) Females. 



(rf) AlLinriividual>. 



12 



-! -1 

 3 5 

 5 



3456789 10 11 12 13 14 15 1G 17 IN l.i :J'i :.M ;.'.' 



3 (i "! 311122 5 12 19 22 15 10 2120 IF, 



3 37331445 15 10 13 III 14 4 1 0=129 



G 10 G 4 55 6 7 20 31 32 42 29 10 6 1 ~ 1 0=24r, 



FK;. 22. Variation in tin- diameter of spot 1 in /[iiijiui/itiitia <-<nn-er<jeiin at 



Fairfield, Washington. 



The variability in diameter of spot 3 is given in fig. 23. Here the typical 

 species is at or near 4 units, and the two varieties just mentioned at or 

 near 8 units. The distance of the lateral edge of spot 3 from the suture is 

 given in fig. 24. The lack of bimodality shows that the extension of pig- 

 ment laterad in the variety caseyi is slight, the main extension being 

 toward the suture in this case. The one individual at 27 units was a 

 case of confluence with spot e. 



Table 12 was constructed to test the correlation of these color-patterns 

 with differences of size or shape. We see in them that the pronotum is 

 broader in proportion where there is confluence than where there is not. 



TABLE 12. Comparison of ratio of breadth of prmiol urn to length of elytron 

 in a lot of Hippodamia convergens from Fairfield, Washington. 



