ARCTIC BUTTERFLIES CLARK 291 



broods, one in early spring and one in early summer. Dr. W. J. 

 Holland says that in the mountains of western North Carolina there 

 is also an autumnal brood. 



The third group includes five butterflies of boreal, but not Arctic, 

 range. These have only a single brood a year. 



The last group includes five species that range widely throughout 

 the northern hemisphere. These are the mourning cloak {Aglais 

 mifiopa), the common blue {Lycaenopsis argiolus)^ the cabbage but- 

 terfly {Pieris rapae)^ the small copper {Chrysophanus phlaeas)^ and 

 the grizzled skipper {Pyrgus centaureae (pi. 6, figs. 51, 52)). All, 

 with the exception of the last, have at least two broods a year. All of 

 them range far to the northward into the Arctic, or at least high 

 sub-Arctic regions. The common blue {Lycaenopsis argiolus)^ like 

 the little copper {Chrysopharms phlaeas), has an enormous range in 

 both the New and the Old Worlds, and occurs in a bewildering array 

 of local and seasonal forms, with many individual variants. 



The most interesting thing about the common blue in the present 

 connection is that the early spring individuals captured in the vicinity 

 of Washington resemble others caught in the far north near the 

 Arctic Circle, where the butterfly has only a single brood. Later 

 spring individuals resemble individuals of the summer brood in the 

 most northern localities in which a summer brood occurs. But the. 

 mid- and late-summer forms are quite different from any of the forms 

 found in the North. 



In the case of the little copper, the individuals that appear earliest 

 in the spring have the fore wings much lighter in color and with 

 smaller spots than those seen later, and the under side of the hind 

 wings is darker. In other words, they show an approach to the far 

 northern form feild-enl (pi, 6, figs. 49, 50), though the correspondence 

 between the early spring and far northern individuals of the small 

 copper is by no means so close as it is in the case of the common blue, 

 where it amounts practically to identity. 



The same phenomenon is illustrated by the yellow swallowtail 

 {Papilio glaucus). In this butterfly the earliest spring individuals 

 are of the same size and color, with the same long hair on the head 

 and body, as their representatives from farthest north. Indeed, some 

 of the specimens from the vicinity of Washington taken in early 

 spring are quite indistinguishable from others from north-central 

 Alaska. No females have ever been found in early spring near 

 Washington, and it is possible that here this form exists in the male 

 sex only. 



It is perhaps to be expected that in butterflies ranging northward 

 to Arctic or sub-Arctic regions the first individuals to appear in 

 spring in the southern portion of the habitat should resemble those 



111666—35 20 



