12 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



first brood emerging from the pnpa over a short period of two or 

 three weeks only. In these species there is only a single spring form. 

 If it appears early, as in the case of the common copper {CJiryso- 

 phcmus phlae<is hypophlaeas) , it is quite different from the summer 

 form, corresponding to an early-spring form. But if it appears late, 

 as in the parsnip swallowtail {Papilio polyxenes astenas), it is almost 

 or quite identical with the summer form, representing a late-spring 

 form. 



Butterflies with only a single brood show the same phenomenon. 

 Species that appear early and emerge over a long period, like the 

 common f ritillary {Argynnis cyhele — May-October) , have two forms, 

 one smaller and duller and one, which appears later, larger and 

 more richly colored. If they fly for only a short period in spring— 

 a month or so — like the orange tip {AnthochaTis ffenutia) or the 

 early hairstreaks {Incisalia augustinus^ I. h'us, and /. hen7'ici} the}' 

 appear in only a single form, though the earliest individuals are 

 smaller than those that appear later. 



Butterflies with a single brood that do not appear until June or 

 later, like the regal fritillary {Ar'gynnis idalia — middle of June to 

 October), the aphrodite {Argynnis aphrodite — July), the silvered 

 bog fritillary (Brenthis 7;w//m(%-July), the balmony butterfly 

 {Euphydryas phaeton — June and early July), and Leonard's skipper 

 {Ey^ynnis leonardus — September) have only a single form, whether 

 they emerge over a long period, like the regal fritillary, or over a 

 short period like the others. 



It may be remarked that elsewhere in its range Argynnis aphro- 

 dite occurs in two or more forms, and also has a longer season; in 

 the north Brenthis niyrina appears much earlier, has three broods, 

 and occurs in two or more forms ; and in the north Erynnis leonar- 

 dus appears about two weeks earlier than it does in Washington. 



Other District butterflies occur in three more or less well-character- 

 ized forms. A small, light-colored form is the only form found in 

 early spring. In summer a larger and more richly colored form ap- 

 pears in areas with luxuriant vegetation, but is less numerous than 

 the other. In late summer this becomes common, and a third large 

 and very richly colored inactive form appears locally in bogs. 



As an example, the common buckeye {Jvmonia lavinia coenia) in 

 early spring is represented only by small and active light-colored 

 individuals which have survived the winter. In midsummer there 

 appears in meadows, usually in small numbers, a somewhat larger 

 and less active form in which the underside of the hind wings is 

 more or less marked with pink, usually in the form of a long and 

 very narrow irregular triangle running downward from the anterior 

 border toward the anal angle. In late summer this second form be- 

 comes common, and in wet localities a third very dark form appears 



