346 Canadian Butterjiies, 



and slender, terminated by a somewhat abrupt, compressed, obtuse 

 club, consisting of seven or eight joints, and grooved on one side ; 

 "wings opaque, and thickly clothed with scales ; anterior pair nearly 

 three-cornered, the apical angle not very acute ; posterior pair 

 rounded, partly embracing the abdomen, and the discoidal cell 

 closed ; legs long, slender, and alike in both sexes, the anterior 

 pair being perfect ; tarsi terminated by two equal sized booklets 

 much curved, each having a small tooth on its under side ; between 

 these booklets is along fleshy cushion, and each is laterally defended 

 by along conical hirsute appendage; eyes naked ; head rather small. 

 Larvae cylindric,elongated and fleshy, with numerous points or larger 

 tubercles, which emit pale hairs, and are arranged in regular 

 transverse series ; the head small and rounded. Pupae angulated, 

 with a short process in front of the head, and with a projecting 

 lateral appendage behind each of the wing cases, they are attached 

 by a tuft of silk at the tail, and a loose girth round the middle of 

 the body. They do not constantly place themselves in one posi- 

 tion with the head upright, but undergo this state in various po- 

 sitions. 



' This genus is very extensive, the species being distributed over 

 most parts of the globe, but especially in the intertropical parts of 

 the old world, the western hemisphere being comparatively poor in 

 species. The prevahng colour is white, more or less pure, with a 

 black border to the anterior wings, variable in width but seldom 

 wanting. Some of the exotic species are much more varied in their 

 colouring, The underside 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 but in others much less so, the females being 

 distinguished from the males only by a somewhat broader band, 

 or by having the upper wings more rounded at the apex. Such of 

 the larvae as are known feed almost exclusively on the Gruciferoe, 

 especially the species oi Brassicoe, as well as on the Residacece 

 Troioeolice and Capparidece. In some years certain of the com- 

 mon English species abound to an astonishing extent, and at such 

 times the cabbages and other cruciferse in gardens, almost disap- 

 pear under their attacks. It is nearly the only genus of Diurnal 

 Lepidoptera injuiious to man and to keep them in check Provi- 

 dence has provided several small species of hyraenopterous para- 

 sites, {rnicrogaster glomeratus, (&c„) which live within the body of 

 the caterpillar till the latter is about to assume the pupa state, 



