MOTHS AND BUTTERFLIES. 



495 



FIG. 620. Callidryas plulea. 



full bloom." Not one of the least singular habits of these butterflies is that of their 

 migrating from place to place, and being often found far out at sea in immense 

 numbers. 



The most common species of 

 this country is C. eubule, which 

 ranges from New York to Florida, 

 thence extending through Mexico 

 as far south as Patagonia. It is 

 of a bright citron yellow, of a very 

 pure and clear tint, and is a very 

 striking object when on the wing. 

 It is occasionally abundant along 

 the New Jersey coast, particularly 

 about Loncj Branch, and has also 



o * 



been taken on Staten Island. The 



caterpillars of Callidryas are nearly 



always green, while the chrysalis is 



very much widened and flattened 



out in the middle like the deep keel 



of a boat. The great genus Pieris next engages our attention. It contains about one 



hundred and forty species, the bulk of which are natives of the northern hemisphere. 



They are nearly all white, with shades and patches of black, the under side of the wings 



more or less shaded with yellow. In this country are eleven or twelve distinct species, 



one of which, at least, and the most destructive, is an importation from Europe. This 



is P. rapce, which of late years has increased in the United States to such an enor- 

 mous extent as to be a serious pest to the farmer and gardener. It is 

 so abundant as to be rapidly overshadowing one or two other species 

 formerly quite common, and it is feared that, unless very strenuous 

 measures be adopted to check its ravages, this species will, in a few 

 years, overrun the entire continent. Luckily it is well known, and the 

 caterpillar can, by watchfulness and attention, be gathered in large 

 quantities and destroyed. It is needless here to do more than briefly 

 allude to the parasites which keep it in check, or to the energy displayed 

 by our various agricultural societies in combating this insidious foe. 

 Some idea of its depredations may be gained from the statement that 



the loss of cabbages and kindred plants by this species in the state of New York alone 



amounts yearly to several thousands of dollars. 



Another species of destructive habits, but less 



abundant than P. rapce, is P. oleracea, " which 



feeds on various plants besides cabbage, such as 



brocoli, cauliflower, turnip, radish, and mustard," 



and is popularly known as the pot-herb butterfly. 



The Iarva3 of this species are dull green, covered 



with a very fine pubescence. P. protodice does 



some damage also to garden plants, but is found 



more sparingly than the other two species, though 



it extends its range quite across the continent, being in some seasons abundant in Cali- 



fornia. P. brassiccv and P. napi are also determined enemies of the agriculturist, and 



IG aiis of 



FIG. 622. Pieris oleracea. 



