riERiD.-r.. 21 



Genus 2. PIERIS, Sckrmik. 



Antennre long and slender, distinctly clubbed. Wings 

 opaque, creamy white, tips of fore wings blackish and rather 

 pointed. 



Laeva downy, gregarious in some species, but not under 

 a common web, feeding mainly on cruciferous plants. 



1. P. brassicse, Z. — Expanse, 2| to 2f inches. Wings 

 ample, creamy white, tips black. Female with large black spots. 



Creamy white, fore wings of the male having the base and 

 costal margin blackish. Apex broadly black, often dusted 

 with whitish scales, and having internally dashes of black 

 along two or three nervures. Hind wings with a small 

 black costal spot. The female has a broader apical black 

 blotch, and two large black spots on the outer half of the 

 fore wings, from the lower of which a black blotch runs along 

 the dorsal margin. 



Under side of the male having the fore wings creamy white, 

 with yellow costa and apex and two large black sjiots ; hind 

 wings dull yellow. Female similar, but with larger spots, and 

 with dusky scales on the hind wings. May and June ; second 

 emergence in July and August. 



Not usually variable, except in the presence or absence of 

 the white dusting on the black apex. Mr. Eriggs, who has 

 studied this variation, says that the form having the white 

 scales is especially common in the Midland counties and again 

 in the Orkneys, but that the black-tipped form preponderates 

 in both the north and south of England. At Sligo, Mr. Russ 

 has taken a large dusky form of the female, with the black 

 apical blotch much exaggerated, and throwing off strong black 

 streaks inwards as far as the upper spot. From the north of 

 Ireland a very small form has been obtained. Mr. Mosley 

 records a sulphur-yellow male ; and in the collection of tlie 

 late Mr. N. Cooke, in the Liverpool Museum, are specimens 

 with dusky nervures, and others with yellow cilia. Some, 



