BUTTTERFLIES OF THE DISTRICT OF COLUMBIA 31 



until recent years a very common butterfly in boggy spots, and its 

 caterpillars occurred abundantly on the false nettle {Boehraei^ia cyl- 

 indrica) ; but it was scarce in 1927 and 1928. From early in May 

 until well into August in these fields and throughout the woods 

 adjacent the zebra swallowtail {Papilio riiarcellus) is not at all 

 uncommon, and its eggs are often found on the scattered papaw 

 {Asiniina triloba) bushes. Not very far away along Conduit Road 

 I once early in summer observed the giant swallowtail {Papilio 

 GJ^esphontes) , but its occurrence in this immediate vicinity is only 

 casual, 



A somewhat different picture is presented by the higher rolling 

 grassy country in the vicinity of Silver Spring, Md. 



Here about the thistles the black swallowtail {Papilio polyxenes) 

 is the most abundant of the larger butterflies in the open fields, the 

 yellow {Papilio gflaucics) and the spicebush {Papilio troilus) swal- 

 lowtails near the woods. The blue swallowtail {Papilio philenor) 

 is rather scarce and is far outnumbered by the others. The monarch 

 {D annus plexippus) appears occasionally throughout the region and 

 tends to linger in the damper hollows. The American painted lady 

 {Pyrameis virginicns-ls) is to be met with everywhere on clover or on 

 thistle flowers. Seen mostly on the drier higher areas are the com- 

 mon copper {Chrysophanus phlaeas) and the sooty skipper {Pholi- 

 sora Catullus), both very few in numbers, and the cabbage butterfly 

 {Pieris rapae) , which here is fairly numerous. On the drier uplands 

 and along the roads and also in the marshy hollows the buckeye 

 {Junonia lavinia) is fairly numerous ; those in the damp localities as 

 a rule are larger and somewhat more highly colored than the others 

 and usually streaked with pinkish on the underside of the hind 

 wings. Confined to the marshy areas are the females of the regal 

 fritillary {Argynnis idalia) and the Leonard's skipper {Erynnis 

 leonardus) and to the vicinitj'' of tree-lined streams the gray darter 

 {Pyrgus tessellatus) , which is very common. Local and rather scarce, 

 seen mostly along the weedy roads, is the lesser sulphur {Eurenia 

 lisa) . 



The other butterflies occur in about the same relative proportions 

 as at Cabin John, but there is a greater variety of the smaller 

 skippers. 



In 1926 and 1927 the painted lady {Pyrameis cardui) and the 

 azure hairstreak both were common here, but they were absent in 

 1928, 1929, and 1930. 



A drive along the woodland roads anywhere in this region in the 

 middle of September discloses the spicebush swallowtail {Papilio 

 troilus) and the black emperor {Basilarchia arthemis a^tyanax) in 

 almost equal numbers, both being seen as scattered individuals, 

 neither abundantly. The hop merchant {Polygonia comma), the 



