70 



EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES. 



Subspecies of North America: The typical condition in Europe is not 

 common with us. The variety parvula far exceeds it in numbers. 



The case of the variety humeralis is especially interesting. In the East- 

 ern States where A. bipunctata is found, many specimens with this pat- 

 tern belong to A. bipunctata, as is known by the cross-breeding obtained 

 by Burgess. The humeralis pattern is found, however, throughout the 

 Rocky Mountains and Pacific States, where A. frigida and annectans occur 

 but not A. bipunctata. In fact, this pattern is more abundant there than 

 in the East. Since the two species are closely allied and each is known to 

 give many variations in the melanic direction which show many analogies, 

 I believe that this pattern exists as a variety of each. It becomes neces- 

 sary to consider these western specimens as variety humeralis of A. frigida 

 or variety humeralis of A. annectans. 



TABLE 18. Heredity in Adalia frigida. 



Three specimens that were kindly sent to me by Mr. G. W. Dimmock, 

 of Springfield, Massachusetts, that proved to be impregnated females with 

 spots 2 and 3 only, gave offspring as in table 18. It will be noticed that 

 where spots 4 or 5 are present at all they are well developed, thus consti- 

 tuting a unit-character. 



b c d e f 



FIG. 72. Variation in pronotal pattern in Adalia fri</i<fu. 



3063. Adalia annectans Crotch. 



Distribution: Western States and British Columbia. 



Lack of intergrades and of breeding experiments make it desirable to 

 retain the specific status of this pattern for the present, in spite of its 

 close relation to A. frigida. (See fig. 71.) 



Typical pattern: Spots a, 1, 2, 3, 4, 5, 6, 7. The numbering is that of 

 Weise, with 6 the humeral spot, and 7 next it. 



