78 



EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES. 



with this difference, that the confluence will crop up in some of the 

 progeny nearly if not quite to the full degree. Even though there is seg- 

 regation of the germinal representatives of these characters, fluctuation is 

 so great as to obscure it. The explanation of these facts on the basis of 

 blending heredity seems at first more satisfactory. The difficulty with 

 that hypothesis is the failure of these variations to have long since disap- 

 peared by swamping. We may assume that variations in the direction of 

 confluence are determined and that they continue to appear from time to 

 time. Their failure to carry the whole species to a greater degree of con- 

 fluence is probably checked by selection either in hibernation or through 

 predaceous foes or by subponderance. 



TABLE 19. Heredity in Epilachna borealis. 



[C. S. H.=Cold Spring Harbor.] 



* The individual with 2+3 was 1 + 2 + 3 on one side. 



t Pigment along suture towards base in one. 



I Both having o ap. 7 had ~i a p. or -(- 6. 



^ Pigment along suture towards base in one. 



Epilachna toweri n. sp. 



Distribution: Texas (Comal County). 



This species most nearly resembles E. borealis Fabricius. The pigment 

 area is reduced, but along the lines of variation seen in E. borealis. The 

 space between the two median spots on the pronotum is about one-half 

 the length of the pronotum. The caudo-mesal spot is free from the caudal 

 margin of the pronotum. The lateral pronotal spots are about one-fourth 

 the length of the lateral part of the pronotum. The mesal spot of the 

 intermediate row on the elytra is not confluent with the suture. So far as 

 color-pattern goes, these beetles would not be given more than subspecific 

 status. There is, however, a difference in form that is distinctive. The 

 elytra are more convex, increasing the ventro-dorsal dimension. In the 

 basal part of the elytra the slope is only slightly curved, as shown in fig. 

 89. The area between the two humeral spots is thus flattened and the 



