BUTTERFLIES OF THE DISTRICT OF COLUMBIA 169 



the wing. I have seen only four or j&ve engaged in feeding, all of 

 them on the flowers of Barbarea 'vulgains. The summer form, 

 however, like all our summer pierids, is very fond of flowers. 



When engaged in feeding the habits of Pieris frotodice are very 

 much like those of P. raipae^ but it is less active and much less shy, 

 so that if may often be taken with the fingers. Its flight from flower 

 to flower is weaker and less energetic than that of P. rapae. The 

 relative activity of these two species when feeding much resembles 

 that between the yellow clover butterfly {Colias philodice) and the 

 stronger orange species {C eury theme) . 



So far as I have seen the females of this species always feed with 

 the wings closed over the back, but the spring males frequently feed 

 with the wings extended horizontally, and the summer males com- 

 monly, or perhaps usually, feed with their wings parted at an angle 

 of 90°. 



Seasons. — This species probably appears here about the third week 

 in March, flying through April and May and the first half of June. 

 The second brood appears in July — probably toward the end of 

 June — and flies until the advent of the third brood toward the end 

 of August. Individuals of the last brood are on the wing until the 

 end of the season. 



Spring forms. — In the early-spring form the groinid color of the 

 wings above is clear chalky white in both sexes. The bases of the 

 wings are heavily infuscated with dark gray, and the markings 

 above are more or less reduced, but in the females more blackish 

 than in the later forms. The spot near the inner (lower) border of 

 the fore wings, about two-thirds of the distance from the base to the 

 lower angle, is absent in the males and absent or greatly reduced in 

 the females. Beneath, as described by Mr. Scudder, the hind wings 

 are broadly and heavily banded with darldsh olive-gray, there being 

 between the bands only narrow more or less wedge-shaped bars 

 of white before a sharply serrate narrow blackish-gray band in 

 the middle of the outer half of the wing which caps more or less 

 obscure tall whitish lunules. The males are as heavily marked on 

 the hind wings beneath as the females, though in them the olive-gray 

 is very slightly lighter. In flight this form appears distinctly 

 grayish. 



The fore wings measure 21 mm. in length in the males and 22 mm. 

 or 23 mm. long in the females. 



The late-spring form resembles the summer form, but it is rather 

 less extensively marked above, and the females, though somewhat 

 dingy as compared with the early-spring females, are of a purer 

 white. Beneath, a few of the females are marked almost exactly as 

 in the summer form, but most of them have the hind wings marked 

 essentially as in the early-spring form, though the markings are 



