60 



EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES- 



MODIFICATION AND HEREDITY. 



The application of 40 C. to the prepupae and pupae did not affect the 

 pattern. The results of the experiments in heredity with this species are 

 summarized in table 17. Since on Long Island the variety conjuncta was 



present in a ratio of 4 per cent, and each of 

 the other varieties was found in less than 0.1 

 per cent, the mates of females from nature 

 were probably normal. The progeny of such 

 a female (278) are represented in fig. 52. They 

 are remarkable, since 40 per cent of the prog- 

 eny surpass the unusually pigmented mother in the amount of confluence 

 of spots. It is hard to believe that this is! not determinate. The lack of 

 intergrades between the 4 normal specimens and those like the mother is 

 striking, especially in comparison with the experiment of 440 ?, and with 

 the presence of such intergrades in nature. In general, the conclusion is 



TABLE 17. Heredity in Coccinella novemnotata. 



FIG. 50. Variation in pronotal 

 pattern in Coccinella novemno- 

 tata. 6= mode. 



Progeny of 405. 



justified that there are here a number of positions of organic stability, 

 namely, h+l, h+l+m, m+a, h+l+m+a; h+m was never seen without 

 other confluence either in these experiments or wild. In progeny from 

 465 ? (fig. 53) we see that an unusual shape of the humeral spot is inherit- 

 able. The amount and kind of intergradation varies in fraternities from 

 different parents, and from this we may infer that we are not dealing with 

 sharp-cut unit-characters, but rather with positions of organic stability 

 not finely localized. 



