24 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES. 



Var. moesta Leconte: 



The black area extended so as to leave only a small basal lunette and a small area 

 between 4 and 6 of the reddish ground-color. Northern California to Vancouver Island and 

 British Columbia between Hope and Okanogan. Limited to the humid Pacific Coast 

 region. I have been unable to obtain living specimens. There is reasonable doubt as to 

 whether this pattern may not constitute a distinct species, especially since at Dilley, Ore- 

 gon, where the spotless variety prevails, one has been taken. It is clearly a melanic 

 derivative from a spotted Hippodamia. Two specimens with pigment reduced enough to 

 reveal the unobscured pattern are shown in fig. 13. While they do not agree in showing 

 one direct line of development, it is probable that it is through var. quinquesignata. It 

 is likely, moreover, that the beetles have some such pattern when newly emerged from 

 the pupa, as Miss Isabel McCracken has shown for the melanic variety of Melasoma 

 scripta, and that the variation in these when known will make the ancestry of var. moesta 

 clear. The modification experiments uponH. convergens prove that a cold environment in- 

 creases pigmentation. The degree of cold was such, however, that the beetles suffered 

 more or less damage, and still they fell far short of the melanism of the variety moesta. 

 Moisture alone produced no effect. For this reason and because Dilley, Oregon, has typical 

 var. moesta rarely along with the spotless H. convergens, I believe that H. moesta is an 

 inherited condition and not an "ontogenetic species." It remains to be seen whether it 

 belongs to the intergenerating unit of H. convergens or not. 



FIG. i:!. Variation of color-pattern of var. moesta. with twointergrades. 

 e =-- mode ; b, from Humboldt County, California. 



Examination of these varieties shows that they are the several combina- 

 tions of a number of characteristics, as follows: 



1 to 7. The mark and the spots 1, 2, 11. The confluence of 1 and 3. 



3, 4, 5, 6, respectively. 12. The confluence of 4 and 5. 



8. The new spot e. 13. The confluence of 4 and 6. 



9. The new spot q. 14. The confluence of 5 and 6. 



10. The confluence of and 3. 15. The melanism of var. moesta. 



The combinations of these characteristics produce the different vari- 

 eties given and the numerous ones not given, characterized by loss of 

 certain spots. The distribution of some of the characteristics is given in 

 tables 4 and 5. 



The pronotum is subject to a similar remarkable variation (fig. 14), and 

 this, strangely enough, is not highly correlated with the coloration of the 

 elytra. Spotless elytra, as well as the typical spotted pattern, are asso- 

 ciated with all or nearly all of the pronotal patterns. The typical pronotum 

 is black, with 2 light convergent discal marks and a narrow light margin. 

 The black area is slightly emarginate mesocephalad and the white margin 

 is slightly narrower laterad and broader cephalolaterad and caudolaterad. 

 The convergent marks may, on the one hand, disappear, or, on the other 

 hand, break through to the margin, generally at a point in the continuation 



