BUTTERFLIES OF THE DISTRICT OF COLUMBIA 251 



It closely resembles /. augustinus^ but is duller below. The dark 

 inner half of the undersurface of the hind Avintrs is bordered by a 

 narroAv Avhite line, beyond which is an irregular liohlly frosted band 

 bounded outwardly by the roAv of small spots in the light outer half 

 of the wing- the wing is margined by a fine line of white, but the 

 area between this marginal white line and the row of spots is brown 

 with no light scales. On the underside of the fore wing the area 

 between the irregular line crossing the middle of the outer half of 

 the wing and the row of small spots midway between this and the 

 border is usuall}^ more or less frosted. 



Family PAPILIONIDAE 

 Subfamily Pierinae 



ZERENE CAESONIA CAESONIA (Stoll) 

 Dog's-hbad Clover 

 Plate 28, Figure 5 



There are two specimens of this species on exhibit in the District 

 collection in the National Museum. I have never seen it in this 

 region, nor do I knoAv of any District specimens. 



Late in summer the variety of the female of the yellow clover 

 {CoVtas pJiilodicc) in which the outer border of the fore wings is 

 solid black without the usual included yellow spots is easih' mistaken 

 for this butterfly. 



The dog's-head clover is common in the South and has been 

 reported from many localities north of the District, so that its occur- 

 rence here as a casual is to be expected. 



PIERIS VIRGINIENSIS Edwards 



Plate 56, Figures 3, 4 



This butterfly is easily distinguished from the Euroi)ean white 

 {Pier is rapae) by the absence of black spots and the absence of yellow 

 on the underside. It is less active than the latter, with a weaker 

 flight. There is no record of its occurrence in the District, but it is 

 found in the high lands locally from New York to North Carolina. 

 It may be represented in old collections from the District. 



Dr. William T. M. Forbes writes me that Pieris virglniens-is is 

 probably distinct from P. napl oleracea^ as it is single brooded, 

 whereas the northern P. n. oleracea is double brooded. He tells me 

 that his most northern record for P. virginiens/s is the southern slope 

 of the Adirondacks, while he has seen no authentic specimens of 

 P. n. oleracea from south of the Mohawk Valley. 



