HOW TO KNOW THE BUTTERFLIES 



The Compton Tortoise 

 Eugonia j -album (Eu-go'ni-a j-al'bum) 



Fig. 34 



This butterfly resembles in its general appearance those of 

 the genus Polygonia, but it is sharply distinguished from them 

 by the inner margin of the fore wings being nearly straight, 

 by the heavier markings of the fore wings, and by the pres- 

 ence of a whitish spot on both fore and hind wings, near the 

 apex between two larger black patches. On the lower sur- 

 face of the hind wings there is a small L-shaped silvery bar. 



Caterpillar. — Length one and one-half to two inches. It 

 is greenish in color, more or less speckled and striped with 

 lighter hues. Its head and its body bear black, bristly spines 

 like the caterpillars of the preceding genus. The caterpillars 

 feed in flocks and are rarely found. 



Food-plants . — White birch and willow. 



This butterfly, though larger than the Poly- 

 gonias, strikingly resembles them in the cut of the 

 wings, except that the inner margins of the front 

 wings are straight. Not because it is so slow 

 is it called tortoise, but because of the shades 

 of brown and red and ochre yellow beautifully 

 blended on the upper surface of its wings which 

 resemble the tints of the tortoise-shell. The white 

 spot on each wing is so placed as to heighten by 

 contrast the rich velvety hues. While its color- 

 ing above is quite different from that of the Pol- 

 ygonias, it is very like them in the intricate pat- 



146 



