24 



i:n"jurious insects 



In the perfect bntterfly the body and head are blacky 

 and the wings white, marked with black, as follows: In 

 the female (fig. 16), a small space at the tip, and three 

 spots on the outer half of the front wings, and one spot 

 on the hind wings; beneath, one spot on the front wings, 

 but none on the hind wings, which are commonly yel- 

 lowish, sometimes passing into green. The male (fig. 17) 



has only one spot above 

 and two beneath on the 

 front wings, and a black 

 dash on the anterior 

 edge of the hind wings. 

 There is a yariety of the 

 latter sex which has the 

 same markings, but dif- 

 fers from the type in 

 the ground color being 

 canary yellow. Curiously enough, this yariety has been 

 taken both in this country and in England. 



These butterflies occasionally assemble in great num- 

 bers. At one time a flight crossed the English channel 

 from France to England, and such was the density and 

 the extent of the liying mass, that the sun was completely 

 obscured for a distance of many hundred yards from the 

 people on board a shij) that was passing underneath this 

 strange cloud. 



Fig. 17. 



RAPE BUTTERFLY {PkHs ropce). 



THE POT-HERB BUTTERFLY. 



(Pieris oleracea, Boisd,) 



This species has a yery wide range, reaching rarely as 

 far south as Pennsylvania, extending eastward to Nova 

 Scotia, and at least as far west as Lake Superior, while 

 in the north it is found as high up as the Great Slave 

 Lake in the Hudson Bay Company's territory. This 



