284 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



dimorphism occurs, the hibernating form being known as var. har- 

 risii and the summer form rar. dryas, though the distinction is not 

 as marked in this species. 



The half-grown larva is black, with a yellowish stripe along the 

 side from the third segment, and with yellow stripes across the 

 back, and spots of the same color at the base of the dorsal spines, 

 which are yellow tipped with black. The mature caterpillar is 

 white, mottled, or striped with gray or ashen, and with red 

 spiracles. 



The butterflies of both species arc of a rich brown color, marked 

 with black and tipped with lilac above, and of a much darker pur- 

 plish brown with the characteristic silver spots beneath, which are 

 well indicated in the illustration. 



Remedies. Spraying with an arsenical will destroy the larvae 

 when such treatment becomes necessary. 



