LEPID OP TERA . 383 



surface of the hind wings are pale lemon-yellow. In the 

 female there are two spots on the outer part of the fore 

 wing besides the black tip, in the male only one (Fig. 

 462). There is considerable variation in the intensity of 

 the black markings, and in the extent of the yellow tinge of 

 the wings. 



The larva of this species (Fig. 461) feeds principally on 

 cabbage, but it also attacks many other cruciferous plants. 

 Its color is the green of the cabbage-leaf, with a narrow, 

 greenish, lemon-yellow dorsal band, and a narrow, inter- 

 rupted stigmatal band of the same color. The body is 

 clothed with very fine short hairs. 



Pieris rapce is without doubt the most injurious to agri- 

 culture of all our species of butterflies. It is an introduced 

 species, but has spread over the greater part of this coun- 

 try. As it is three-brooded in the North and probably 

 more in the South, it is present nearly the entire season, so 

 that it needs to be fought constantly. Owing to the im- 

 practicability of using poison upon cabbage, and to the fact 

 that the larva bores into the heart of the cabbage beyond 

 the reach of applications to the plant, it is an exceedingly 

 difficult insect to combat. Obviously it is important in 

 fighting this insect to thoroughly subdue the spring and 

 summer broods, so that the bulk of the fighting can be 

 done before the cabbage begins to head. For this purpose 

 pyrethrum and kerosene emulsion have been found most 

 useful. 



The Gray-veined White, Pieris oleracea (Pi'e-ris ol-e-ra'- 

 ce-a). The wings are white above and below, with a scarcely 

 perceptible tinge of greenish yellow. Sometimes there is a 

 dark spot on the fore wing between veins V s and VII, , but 

 usually the wings are unspotted. The base of the wings, 

 however, aiid the basal half of the costa of the front wings, 

 are powdered more or less with dark scales, and the veins of 

 the wings, especially on the lower side, are grayish. 



This species occurs throughout Canada and in the more 



