48 



EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES. 



these cases the pronotum was lacking pigment at an independent center 

 the caudal margin of the pronotum. The variation of the color-pattern 

 of the head is given in fig. 31- 



HEREDITY. 



Table 16 epitomizes the results of the heredity experiments with respect 

 to the elytral pattern. No. 368 ? has a pronotum with pronotal dashes open 

 to the margin cephalad. None of the 18 offspring possess the character- 

 istic. Since the same characteristic is inherited in H. convert/ens (375?), 

 it is probable that its lack in the offspring here is the result of recessive- 

 ness or subponderance. 



TABLE 1(>. Heredity in Hippodamia spuria. 

 [For description of form of table and abbreviations sec table 15, pp. 42, 13.] 



In the elytral pattern the table shows that the sutural mark is inherited 

 segregately, with some intergradation. We have two centers of variation, 

 but not two unit-characters. The long sutural mark is neither recessive 

 nor dominant, nor is there any regular dominance in the relation of spots 

 4 and 5. There seems to be a preponderance of short sutural pigment 

 and of 4 + 5, which are more common than the opposed conditions. 



3048. Hippodamia oregonensis Crotch. 



Distribution: Cascade Mountains. 



Although the pattern of this species (see fig. 32) is parallel to that of 

 H. convergens var. quinquesignata, a collection of the 2 from Pinnacle 

 Peak, Washington, shows a difference in form of body and shape of the 

 spots. This makes it probable that it has been derived from H. spuria 

 by the addition of the banding character. The possible influence of 



