BUTTEBFLIES OF THE DISTRICT OF COLUMBIA 41 



in the woods, and especially along the banks of woodland streams, 

 while the females range widely over open fields. Both sexes are 

 found together only along the borders of damp woods. Such a selec- 

 tive distribution of the sexes is frequent among butterflies in tropical 

 America. In New England, according to my experience, the two 

 sexes of both of these butterflies inhabit the same territory. 



Mr. Scudder noticed that in New England among the species of 

 the genus Thanaos the females are always less abundant than the 

 males and seldom or never leave their natural haunts, which are 

 overgrown recent clearings, or the thickets and woods themselves, 

 while the males are more fond of the neighboring roads, playing 

 about damp spots, and resting with spread wings with a tameness 

 quite foreign to their nature in the thickets. 



In this region the males always outnumber the females and are 

 much more generally distributed. But further generalizations based 

 upon conditions in New England hold good only for T. hrizo. T. 

 icelus here is very common in damp, open fields, often at a consider- 

 able distance from any woods, while T. juvenalis is also common in 

 open country. In both of these species females, as well as males, are 

 found in the fields. The other species also occur in open country as 

 well as in the woods. In those species having a second brood, the 

 individuals of the second brood have only been found in fields, but 

 this may be due to the fact that during summer and autumn the 

 woods have not been thoroughly searched for them. 



It may be mentioned that early in spring, before the appearance 

 of the leaves, T. juvenalis, which here as well as farther north is the 

 first to emerge, is frequently seen flying about the higher branches 

 of trees 20 feet or more above the ground. It is not known to do 

 this in the north. 



Though in the north Bre7ithis myrina and B. hellonoj are commonly 

 found together, in this region they part company. Only B. myrina 

 is found in the vicinity of Washington, while in other places, as 

 about Lewiston, W. Va., I have found only B. hellona. 



In New England the caterpillars of the yellow swallowtail {Pa- 

 pilio glaucus) and of the mourning cloak {Vanessa antiopa) are very 

 commonly found on shrubs, bushes, and small trees — wild cherries, 

 willows, and poplars — within from 3 to 6 feet of the ground. In 

 the District area the caterpillars of both of these butterflies are very 

 seldom found, as they seem always to live high in the trees. 



The food plants of Brenthis myrina and of Argynnis idalla in 

 this region should be determined. In the locality where the former 

 is found there are no violets, while the latter freely deposits its eggs 

 on a considerable variety of plants in open fields where violets do 

 not occur. 



