162 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



as in G. euryiheme. In the white female it varies from pale straw 

 yellow to bright red-orange. 



There is also much variation in the black spot at the end of the cell 

 on the fore wings. This is usually about twice as long as broad in 

 the males and from one-half to one-third again as long as broad in 

 the females. In both sexes it often bears a prominent tooth in the 

 middle of the apical side. In the males it is sometimes reduced to a 

 narrow black line, and in the females rather frequently and in the 

 males occasionally it has a conspicuous yellow (or white) center. 



White females frequently are flushed with yellow on the hind 

 wings from the abdominal border as far as the cell and vein Mi, 

 where the yellow abruptly ends and also, less strongly, in the cor- 

 responding area on the fore wings. In some cases this yellow is 

 bright and very conspicuous. In all such specimens which I have 

 seen the hind wings are shaped like the hind wings of Zerene cae- 

 sonia, and the outer margin of the fore wings is nearly at right 

 angles to the inner, while the black margin of the hind wings is 

 reduced and resembles that in Z. caesonia. 



Rarely females occur which are deep, almost chrome, yellow on 

 the fore wings and have a pronounced orange flush on the hind 

 wings. One such female was taken at Silver Spring, Md., on August 

 6, 1927. On the wing it was mistaken for C. eurytheTne form ariadTie. 

 This might possibly be considered as a hybrid with G. eurytheme 

 were it not that I have an exactly similar female, somewhat larger 

 and with larger spots in the black margin of the fore wings, taken 

 at Newtonville, Mass., a locality where G. eurytheme is unknown or 

 at least an extremely rare casual, on July 25, 1923. 



Males are not infrequently taken late in summer that have a 

 slight orange flush along the submedian vein and vein Mi on the 

 fore wing. 



The individuals of the third brood seem not to differ from those 

 of the second brood. 



It is worthy of special note that in this region white females are 

 relatively as common early in spring as later in the season, appear- 

 ing with the earliest yellow females of the spring brood. They occur 

 in the spring, however, in only one form, a Avhite replica of the cor- 

 responding yellow females. In eastern Massachusetts white females 

 do not occur in the spring brood. 



Measurements. — Specimens taken up to the middle of July measure 

 in the length of the fore wing: Males 24r-29 mm., averaging 26.0 mm., 

 and females 24-29 mm., averaging 25.7 mm. 



Specimens taken from the middle of July to the end of the season 

 measure : 63 males, 24-31 mm., averaging 26.1 mm., and 57 females 

 24r-31 mm., averaging 27.9 mm. 



