THE COMMON SULPHUR. 



Do not be disturbed if you see the generic name Pontia 

 instead of Pieris; it is probably better. See also Colias 

 for a white butterfly which may confuse you. 



Plate XXXIV shows the male Falcate 



Orange-tip, the orange tip being indicated 



by shading. The female has no such tip 



on the upper surface and neither sex has it below, the 



markings there being light greenish brown. The larva, 



which feeds on rock-cress, shepherd 's-purse, and other 



Cruciferas, is bluish green, with pale dorsal and side stripes, 



but, if you look closely, you can see fine stripes of other 



colors. 



Probably you have noticed that, among 



a flock of yellow butterflies, the Common 



Sulphurs, which rises from a roadside pool 



as you pass, there is sometimes a white individual. This 



is usually an albino philodice and, if so, almost certainly 



a female. However, even when white, the species 



can be distinguished from Pieris by the silvery-centered 



spots on the under side of the wings (see Plate XXXV). 



The common, but rarely noticed, green larvae feed upon 



clover leaves. 



Colias eury theme is about as variable as P. napi but can 

 usually be recognized by the strong orange tint of the 

 yellow on the upper side and the marginal markings which 

 suggest philodice. Its larva feeds on clover. 



Most of us will agree with the Comstocks 

 Meganostoma that the face of the Dog-face (Plate 

 caesonia 



XXXV) is more like that of a duck than of 

 a dog. However, it makes the species easily recognizable. 

 You may find it listed in some books under Colias or Zerene; 

 in nature you will find it from Pennsylvania (very rarely) 

 and southern Wisconsin to the Gulf States. Its larva 

 feeds on false indigio (Amorpha) and (?) clover. 



Catopsilia eubule: Nearly every year strong-flying 

 individuals of this southern species get even further 

 north than Long Island; it has a wing expanse of 2.5 inches; 



137 



