1168 THE BUTTERFLIES OF NEW ENGLAND. 



suffered at the hands of" this interloper equally with the nearer relative of the 

 latter, Picris oleracea. In the west, where only I have seen it abundant, 

 it flies about the low weeds of pastures, waste land and open prairies, but 

 seeks the cultivated field for egg-laying and is fond of the flowers of 

 buckwheat. 



Food plants and habits of caterpillar. The caterpillar has been 

 raised by Mr. Saunders upon cabbage (Brassica oleracea) and by Dr. 

 Chapman upon wild peppergrass ( Lcpidiuni virginicuni) ; it undoubtedly 

 feeds also on other Cruciferae, for Boll states that in Texas it feeds from 

 April to July on a species of Thlaspi and turns to the cultivated plants 

 only after the death of the former; and Dr. Kirtland remarks that "cab- 

 bage or turnip fields, or waste grounds overrun w^ith the shepherd's purse" 

 (Capsella bursa-pastoris) are the usual resorts of the butterfiy. Glover 

 records it on turnip and Bean on mustard. Riley states that it appears 

 to confine its ravages more closely to the cabbage than our other white 

 butterflies, "but is occasionally found feeding upon the turnip." He has 

 also found it doing great injury to sweet alyssum, A. maritimum, "com- 

 mencing at the head and eating down to the base of the plants. We have 

 also found it feeding on mignonette." Mr. Riley once found a chrysalis 

 "fastened to a stalk of the common horse nettle (Solanum carolinense) 

 which was growing in a cemetery, with no cabbages within at least a 

 quarter of a mile" ; doubtless it had fed on other Cruciferae. Mr. Beu- 

 tenmuller tells me that he has taken it at Camden, N. Y., on a species of 

 Erigeron, one of the Compositae ! 



French says that the larvae attack only the outer leaves, never the heart 

 of the cabbage, and thus are less destructive than the caterpillars of Pieris 

 rapae. 



Life history. The insect is triple brooded, each successive generation 

 more abundant than the preceding. The first, indeed, is seldom noticed, 

 the only memoranda of its appearance being in captures in southern Utah 

 by Palmer in April and May, a note by Abbot stating that he took a 

 specimen on May 13, and in Edward's remarks on Pieris vernalis (which 

 is now known to be simply the vernal brood of this species), where he 

 states, "I have taken this species at Coalburgh [W. Va.], in the month 

 of March, it being one of the earliest butterflies of spring." Mr. Bean of 

 Galena, 111., however, speaks of a spring brood in Mayas extremely rare. 

 The second brood appears late in June or early in July (Bean says a few 

 may be seen in Illinois about mid-June and a larger brood in July) and 

 continues until the third brood makes its advent — the last of August ; 

 early in Septeml)cr this becomes abundant, and the butterflies continue to 

 emerge from the chrysalis even into October and fly, at least in the south- 

 ern states, into November. The precise times of the appearance and 

 duration of the insect in its earlier stages are unknown, excepting that 



