1138 THE BUTTERFLIES OF NEW ENGLAND. 



(Trimcn). The fore wings are often somewhat falcate. They are largely 

 an 01(1 World type but the north temperate zone of the New World pos- 

 sesses two or three genera, but none peculiar to it. A single form is 

 found in New England. "Woods and their outskirts are the favourite 

 haunts of the species . . . whose flight is commonly more rapid and long 

 sustained" than that of the Pieridi (Trimen). 



Excepting by Hiibner, no naturalist has before separated this group as 

 one of equivalent value to the Pieridi and Rhodoceridi. The different gen- 

 era have usually been classed with the former, midway between which and 

 the latter they really belong. The study of the early stages, however, 

 will speedily convince any one free from the bias of tradition that the sep- 

 ai'ation we here maintain is well founded. 



The butterflies of this rather small group, like those of the next tribe, are 

 white marked with black, but they are usually further characterized by 

 "a more or less triangular large patch of bright colour occupying the 

 apical portion of fore wings. The colour of this apical marking is most 

 commonly some shade of bright red or orange, often with a lovely rosy 

 gloss" (Trimen, Rhop. Afr. Austr., 42). This bright colored patch is 

 often confined to the males. It has been suggested on several occasions 

 that the marbled green mottling of the under surface of the wings, also 

 characteristic of this group of buttei^flies, has for its purpose the better con- 

 cealment of the insect, as assimilating it to the color of the plants or flow- 

 ers on which it accustomed to alight ; and Kirby suggests that the 

 freqvient absence of the orange spot from the tip of the female may be due to 

 its greater need of protection than the male, since this vivid spot would render 

 it too conspicuous ; while its absence would render it so like the much 

 commoner white species of Pieris that they would not be specially noticed 

 among them. 



The butterflies are eminently butterflies of early spring, and what is 

 remarkable is that they are usually single brooded, matvu'e rapidly and by 

 the end of June at latest in temperate regions, or earlier than that further 

 south, are already in chrysalis from which they do not emerge until the 

 following season. In keeping with this their food is usually found to be 

 those cruciferous plants of a similar habit, that is, which fruit early in the 

 season, and then absolutely disappear from sight, dying down to the 

 ground. In one aberrant type, Zegris, the caterpillar spins before pupa- 

 tion a gauze-like cocoon. 



The eggs are midway in form between those of the Pieridi and the 

 Rhodoceridi, being less fiisiform than the latter and more so than the 

 former, which they most resemble. They are always laid singly. 



The juvenile caterpillars have ranged appendages midway in length 

 between the excessively long ones of the Pieridi and the excessively short 

 ones of the Rhodoceridi ; these are all hollow channels and outlets to basal 



