32 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



question mark {Polygonia interrogationis) ^ and the Camberwell 

 beauty {Vanessa antiopa) from time to time are noticed, and in 

 widely separated places the hackberry butterfly {Ghlorifpe celtis) is 

 common. In the drier woods the yellow swallowtail is seen, and 

 along the woodland streams a few small skippers and occasionally 

 the curious little alder butterfly {Feniseca tarquinius) . 



Perhaps the most interesting locality in the vicinity of Washing- 

 ton is a small boggy marsh on both sides of the road between the 

 Beltsville, Md., railroad station and the experiment farm of the 

 Bureau of Animal Industry of the United States Department of 

 Agriculture. Early in the summer this little marsh abounds with 

 flowers of the buttonbush {G ephala.nthus occidentalis) and of the 

 handsome Spiraea latifolia. Late in summer the numerous tall white 

 flower spikes of Sanguisorba canadensis at once attract attention. 



Late in June and early in July there are found here in great 

 abundance the grass nymph {Satyrodes eurydice)^ the hovering skip- 

 per {Poanes massasoit) , and the pontiac {Atrytone pontiac), and this 

 is the only known locality for the silver-spotted bog fritillary 

 {Brenthis myrina) in this region. 



THE SUCCESSION OF BUTTERFLIES 



About or shortly after the middle of March the Camberwell 

 beauty {Vanessa antiopa) and the hop merchant {Polygonia comma) 

 are frequently seen in the open woodlands. Though occasional indi- 

 viduals, particularly of the larger and more hardy Camberwell 

 beauty, are sometimes to be met with on warm days throughout the 

 winter months, they do not resume the serious business of life in 

 earnest until the conspicuous flowers of the bloodroot {Sanguinaria 

 canadensis) appear above the carpet of fallen leaves. 



A w^eek later — that is, at about the end of the third week in 

 March — these two woodland butterflies are joined by the question 

 mark {Polygonia interrogationis), and at the same time the males 

 of the zebra swallowtail {Papilio marcellus) ^ the orange tip {Antho- 

 charis genutia), the common blue {Lycaenopsis argiolus), and the 

 cabbage butterfly {Pieris rapae) make their first appearance. 



The blues soon become common and in a few days females appear, 

 usually before the first of April. The orange tips and cabbage but- 

 terflies also increase rapidly in numbers, and the females of both of 

 these are to be found during the first week in April. The zebra 

 swallowtails, like these other butterflies, soon become numerous, but 

 the actual date of the first appearance of the females, which are 

 always scarce in this region, is uncertain. 



During the first week in April the first males of the yellow swallow- 

 tail {Papilio glaucus)^ which are always of small size, are on the 



