LEPIDOPTERA 



745 



usually marked with 

 black. They are the 

 most abundant of all 

 our butterflies, being 

 common everywhere 

 in fields and roads. 

 Some species are so 

 abundant as to be seri- 

 ous pests, the larvce 

 feeding on cultivated 

 plants. 



The characteristic 

 features of the vena- 

 tion of the wings are 

 the following (Fig. 

 952) : Vein M2 of the 

 fore wings is more 

 closely connected with 

 radius than with cu- 

 bitus, the latter ap- 

 pearing to be three- 

 branched; vein Ml of 

 th e fore wings coalesces 

 with radius for a con- 

 siderable distance in 



all of our species; and only three or four of the branches remain dis- 

 tinct except in some orange-tips. 



In this family the fore legs are well developed in both sexes, there 

 being no tendency to their reduction in size, as in the three following 

 families. 



The larvcB are usually slender green worms clothed with short, 

 fine hairs; the well-known cabbage-worms are typical illustrations 

 (Fig. 953). The chrysalids are supported by the tail and by a girth 

 around the middle. They may be distinguished at a glance by the 

 presence of a single pointed projection in front (Fig. 953). 



Our genera of this family can be separated into three groups, which 

 seem hardly distinct enough to be ranked as subfamilies. These are 

 the whites, the yellows and the orange tips. 



Fig. 952. — Wings of Pieris protodice. 



I. THE WHITES 



The more common representatives of this group are the well- 

 known cabbage-butterflies. They are white butterflies more or less 

 marked with black. Occasionally the white is tinged with yellow; 

 and sometimes yellow varieties of our white species occur. About a 

 dozen North American species of this group are known. 



