1174 THE BUTTERFLIES OF NEW ENGLAND. 



cremaster; on the second, and especially on the third segment, the ridge is produced 

 or elevated in the middle; a median carina, inconspicuous on the first three segments, 

 but pretty high and ratlier strongly compressed on the succeeding segments, traverses 

 the whole abdomen ; the sides between this and the lateral ridges are sloped, scarcely 

 arched ; beneath the abdomen is well rounded transversely. Preanal button bounded 

 laterally by pretty strongly curved, moderately broad, low, strongly punctate walls, 

 terminating anteriorly in pretty large, equal, rounded, approximate, recumbent 

 tubercles, half as long again as broad. Cremaster viewed from above, rather long 

 and slender, tapering considerably, abruptly docked, half as long again as its medium 

 breadth, deeply chanuelled above, the channelled portion expanding posteriorly ; 

 viewed from the side slender, increasing slightly toward tip, bent a little downward; 

 the apical portion transversely curved, the convexity downward, slender, ouly the cen- 

 tral portion of the field occupied by the booklets, which crowd down the front and 

 back, and form an irregular, rounded mass, broadest below. Hooklets distant, short, 

 the stem rather stout, sliglitly curved, tlie apical portion greatly expanded and curved 

 over so as to have a general direction at right angles to the stem, the extremity 

 broadly rounded. 



This genus is widely spread, extending over all the temperate regions of 

 the northern hemisphere and even reappearing in South America beyond 

 the tropics. In the Old World it spreads from ocean to ocean and from 

 about the parallel of 30° to the polar regions ; in America from about 3,5° 

 N. Lat. to southern Labrador in the east and to the Arctic coast in the 

 west ; several species are found in either hemisphere, but none are common 

 to both, with a single exception of recent importation ; two species are 

 found in New England. 



The butterflies are white, sometimes tinged, especially beneath, with 

 pale yellow ; the markings are mostly confined to the upper surface of the 

 fore wings, consisting of one or two dark spots a little beyond the middle of 

 the lower half, and a dark edging to the apex and inner border ; beneath, 

 grayish fleckings often border the veins of the hind wings. The spring 

 brood differs somewhat from the later ones in the heaviness of the markings 

 and even in the length of the wings ; and sulphur colored varieties of 

 several of the species have been found, in northern localities at least. 



The insects are always at least double brooded and pass the winter In 

 the chrysalis ; they arc among the earliest butterflies, wintering as chrysa- 

 lides, to appear in spring. The eggs are laid on the leaves of wild and 

 cultivated Cruciferae, and are deposited in large numbers upon a single 

 leaf, but are never clustered ; the caterpillars live independently though 

 very many of them may be found upon the same plant ; they live in exposed 

 positions, though generally on the under side of leaves, unless the plant 

 forms a head, as cabbage, when they generally penetrate towards its heart 

 in search of the tenderer leaves. They are thus more destructive to use- 

 ful plants than the caterpillars of any other butterflies. The chrysalids 

 are frequently found attached to palings and hang for from one to two 

 weeks in summer. The butterflies have rather a weak, fluctuating, uncer- 

 tain flight, very different from that of some of the neighboring genera, 



