Ids 



THE AMERICA X NATURALIST [Vol. XLV 



Moreover the color pattern, which is the same in both 

 the typical yellow and the albinic variety of the female, 

 differs in the two sexes to such an extent that they 

 may be distinguished even in flight. The wings of the 



male (Fig. 1) are marked with a solid black band of 

 nearly uniform width extending along their outer mar- 

 gins, whereas in the female (Fig. 2) the marginal band 

 is wider on the fore wings and usually invaded by spots 



of the ground color, but narrower on the hind wings and 

 dusted with scales of yellow or, in the albinic variety, of 

 white. The marginal band on the hind wings of the 

 female in some individuals is absent altogether, the width 

 of the bands in general in both sexes being very variable. 

 Besides these pronounced secondary sexual differences 



