PIERIS. Ill 



Not fewer than one hundred and sixty-six diffe- 

 rent kinds of butterflies are referred to this genus. 

 " They are diffused," says Dr. Boisduval, " nearly 

 over the whole globe, but are particularly abundant 

 in the intertropical countries of the old continent. 

 Considering the extent of the New World, it pro- 

 duces comparatively few species. The most re- 

 markable inhabit Africa, the Indian continent and 

 Archipelago, and New Holland. Such of the ca- 

 terpillars as are known, feed almost exclusively on 

 the cruciferce, residacece, tropiolice, and caparidece. 

 Our P. Cratcegi is the only one in Europe which 

 lives on trees ; but it is probable that many exotic 

 kinds are of the same habits. The prevailing colour 

 among these lepidoptera is white, more or less pure, 

 with a black border, variable in width, but seldom 

 wanting. There are likewise species in which the 

 ground colour is yellow or even orange, while in 

 others it is blackish or blue, &c. The inferior face 

 of the posterior wings generally differs considerably 

 from the upper, and is often very agreeably varied 

 with brilliant colours. The sexual differences, in 

 certain species, are very conspicuous, particularly on 

 the surface; in others, they are much less so, the 

 females being distinguished from the males only by 

 a somewhat wider border, or by having the upper 

 wings more rounded at the apex*." 



* Species ge'neral des Lepidopteres, i. p. 435. 



