22 



The male is well known and common, but the female is scarce, and much 

 resembles Pieris daplidice, from which, however, it may be distinguished 

 by the more rounded tips of the fore-wings, by its shorter antennae, and 

 by having a smaller lunule spot at the centre of the fore-wings. The ground 

 colour is white. The underside of the hind-wings is chequered with green 

 and white. 



The expanse of the wings varies from one and a quarter to a couple of 

 inches. 



Yar. h. Both sexes with a black spot on the upper surface of the hind- 

 wings. 



Yar. c. Both sexes with the black spot on the fore-wings nearly 

 obliterated. 



Var. d. Female with a V shaped greenish-yellow spot on the under surface 

 of the fore-wings, placed between the lunule spot and the inner margin. 

 Yar. e. Male with a large and oblong lunule spot. 



Var./. Differs from the type, by the patch on the fore-wings of the male 

 being yellow instead of orange. 



Yar. g. Male with a hardly discernible orange patch. This variety, which 

 was in Mr. Haworth's collection, is probably an hermaphrodite. 



The egg, which is laid in May or June, is of a yellowish-white colour. 



The caterpillar is green, slender, with a white lateral stripe, and covered 

 with raised dots bearing fine pubescence. It feeds on Cardamine impatiens 

 and other Cruciferse, in July and August. 



The chrysalis is green, with a pink anal tip, and in shape greatly resembles 

 a canoe. 



It has a wide distribution in Europe, and is found also in the North and 

 West of Asia. 



In Britain, Forres appears to be its northernmost limit. 

 Mouffet figured and described it in 1635. 



Genus Y. LEUCOPHASIA. 

 Stephens. 



LeucopHasia. Leukos, white ; phasis, appearance. 



The fore- wings are long and narrow without any discoidal spot, the an- 

 tennae are slender and rather short, the abdomen is rather long and very 

 slender. 



As yet only two species are known, and both are European. 



