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



The pronotum in the dark variety quadrimaculata is black, with only a 

 very light lateral margin which may not be complete. The type and light 

 varieties have a range of variation shown in fig. 70. This exceeds that 

 shown in Europe in the direction of less pigment. The longitudinal median 

 mark fails in only 3 cases in 97. I have not seen any of our specimens 

 with a totally black pronotum, such as is known in Germany. 



From 1 impregnated female of variety rubiginosa I raised 3 beetles; 2 

 were of the typical species and 1 of the variety rubiginosa, with the spot 

 slightly smaller than the parent. The heredity is therefore segregate. 



3066. Adalia frigida Schneider. 

 Distribution: Lapland, Siberia, and United States. 



Typical pattern: Spots 1, 24-3, 4+5. Rare. Found by Casey in Colorado and named 

 by him ornatella (fig. 71). 



Var. immaculata n. var. No spots. Unknown from Europe. 



Var. melanopleura Leconte. Spot 1. Colorado. Unknown from Europe. 



Var. parvula Weise. Spots 2, 3. Our commonest variety in North America. 



Var. siberica Weise. Spots 2+ 3. One from Tyngsboro, Massachusetts. 



Var. fasceta Weise. Spots 1, 2 4-3, 4 + 5. One from Springfield, Massachusetts. 



Var. postica n. var. Spots 1, 2, 3, 4-f- 5. Two from Springfield, Massachusetts. 



Var. hyperborea Paykull. Spots 1 + 2+3, 4 + 5. 



Var. humeralis Say or n. var. Has the pattern of A. bipiinctata var. quadrimaculata. 

 Widely distributed, nowhere common. It is uncertain whether the A. 

 humeralis Say was an A. bipunctata or A. frigida. Since the name quadri- 

 maculata Scopoli antedates it for the variety of A. bipunctata, I apply 

 humeralis to the corresponding variety of this species. 



Weise names 13 other forms showing various other combinations of 

 absence or confluence of some of the 5 spots. Most, if not all of these, 

 will probably be found in the United States eventually. The forms with 

 absence of 4 and 5 constitute a variety as well as those without any spot. 

 The other patterns are forms of the typical species or of these varieties. 



The pronotum shows variation (fig. 72) from an M pattern with 2 lateral 

 spots, in which it approaches that of A. bipunctata, to one with pigment 

 so reduced as to reveal a number of elements nearly identical with those 

 of Cleis picta and Olla abdominalis, closely allied genera. The following 

 forms of pronotal pattern may be recognized. None of these are of var- 

 ietal rank and the amount of pigment has only a low correlation with the 

 amount on the elytra. 



Form A. The M-pattern so reduced that the component elements are readily recog- 

 nized. The lateral spots separate. 



Form B. The M-pattern apparent, and resembling that of A. bipunctata. The lateral 

 spots separate. 



Form C. The M-pattern heavier, with lateral spots narrowly united. 



Form D. The M-pattern much extended, with lateral spots broadly united, the pigment 

 encroaching so as to leave 2 light spots at caudal margin instead of 1. 



