THE AMERICAN ENTOMOLOGIST. 



75 



The first, species we shall mention is the Rape 

 Butterfly {Pieris rapw, Schrank, Fig. 48). 

 This insect has been the occasion of some little 

 speculation and great interest to our New Eng- 

 land and Canadian entomologists, inasmuch as 



[Fig. 48.] 



Colors— Black ami white. 



it has been introduced to this country from 

 England, and is probably one- of the most per- 

 fect instances on record of any insect being im- 

 ported from one country to another and becom- 

 ing completely naturalized in its new quarters. 

 There does not seem to be the slightest doubt 

 that this is the English species. It was proba- 

 bly introduced in 1856 or '57. It was first taken 

 in Quebec in 1859, and in 1803 it was captured 

 in large numbers by Mr. Bowles in the vicinity 

 of that city. As the eggs are laid on the under- 

 sides of leaves, it was probably introduced in 

 this form, the refuse leaves being thrown out 

 of some ship; after which the larvie hatched, 

 and finding themselves in the neighborhood of 

 their food, ate and flourished. Being, moreover, 

 hardy little fellows, they were perfectly able to 

 endure a change of climate. In 1864 it had 

 spread about forty miles from Quebec as a cen- 

 tre; in 1866 it was taken in the northern parts 

 of New Hampshire and Vermont ; in 1868 it had 

 advanced still farther south, and was seen near 

 Lake "Winnepesaugee ; and finally this last sum- 

 mer it was taken around Boston, Mass., and a 

 few stray specimens in New .Jersey. There 

 seems to be no doubt that this destructive in- 

 sect will, in a few years, spread over the whole 

 of temperate North America; for (he other spe- 

 cies of the genus have an extensive geographi- 

 cal range, and not being particular as to its 

 food, it will have no difliculty on that score. 

 Indeed, the larva and pupa seem to have an un- 

 usual power of accommodating themselves to 

 circumstances,— for instance, Mr. Curtis, in his 

 Farm Insects of England, states that the cater- 

 pillars have been found feeding on willow. 



iS^pw let us look at the larva (Fig. 49 a), and 

 its habits. It is one and one-half inches long; 

 pale green, finely dotted with black; a yellow 

 stripe down the back, and a row of yellow spots 

 along each side in a line with the breathing 

 holes. In England and around Quebec it has 



Colors 

 green; 

 iowish-broVu . 



done immense damage to the cabbages and other 

 CrucifersB (Cress Family) by boring into the 

 [Fig. 49.] very heart of the plant, instead 

 of being content with the les.s 

 valuable outer portion, as some 

 other species are. On this ac- 

 count the French call it the 

 "Ver du Cccur," or Heart- 

 worm. When about to trans- 

 form, it leaves the plants on 

 which it has been living, and 

 fastens itself on the underside 

 of some stone, plank, or fence- 

 rail, where it changes into a 

 chrysalis in the middle or latter 

 -(a) pale part of September, and in 



i; (6) yel- '■, . . , , 



• ■ this stage it hyberuates, pro- 



ducing, in New England at least, the perfect 

 insect early in April. The chrysalis or pupa 

 (Fig. 49 b), is variable in color, being some- 

 times yellowish-brown or yellow, and pass- 

 ing thence into green, speckled with minute 

 black dots. The brood of butterflies that emerges 

 from the pupa state in the spring lays eggs 

 shortly afterwards, and these eggs produce cat- 

 erpillars, which in their turn change to chrysa- 

 lids in June, and in seven or eight days more 

 the butterfly appears, which again lays its eggs 

 for the second brood, which, as before stated, 

 hyberuates in the pupa state. 



In the perfect butterfly the body and head are 

 black and the wings white, marked with black 

 as follows: In the female (Fig. 48) a small space 



[Fig. 50] 



Color.^ — Black and white. 



at the tip and three spots on the outer half of 

 the front wings and one spot on the liind wings ; 

 beneath one spot on the front wings, but none 

 on the hind wings, which are commonly yel- 

 lowish, sometimes passing into green. The male 

 (Fig. 50) has only one spot above and two be- 

 neath on the front wings, and a black dasli on 

 the anterior edge of the hind wings. There is 

 a variety of the latter sex which has the same 

 markings, but difl'ers from the type in the ground 

 color being canary yellow. Curiously enough, 

 this variety has been taken both in this country 

 and in England. 



