
130 THE GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 
eastward. In 1864 it had crossed the Mississippi, and now 
it has covered half of the State of Illinois.* 
Three common species of butterflies in Eastern North 
America, — Vanessa Antiopa, Cynthia cardui, and Cynthia 
Atalanta,—long known to be identical with European spe 
cies, have been asserted to be natives of this country, and 
the possibility of their introduction from Europe has recently 
been questioned.t But, within a very few years, there has 
been a well-authenticated instance of the naturalization of an- 
European butterfly in Canada. Pieris Rape, the Cabbage 
butterfly of Europe, was introduced at Quebec about 1859, 
and, in 1863, it had become very abundant within a circle of 
forty miles radius about that city.t If butterflies are intr 
duced and spread so rapidly now, there is no reason why 
the other butterflies mentioned, all of which feed upon it- | 
troduced plants, should not have been introduced and dit 
fused over all the eastern part of the country long before 
entomologists began to study the distribution of species. 
n’s influence is perhaps more noticeable in restricting 
the range of, or wholly destroying many species of animals. 
Within a few centuries several of the largest birds have 
become extinct through his agency, the larger wild anim! l 
have been mostly driven from civilized countries, the rele 
tive abundance of the different classes of animals has been 
materially changed, and the natural harmony which must 
| have prevailed in the distribution of life has been destroyed 
for man cannot change the relative abundance of & ing® 
species without affecting indirectly myriads of animals. 
f man has wrought such vast changes within the si! 
period of our written history, what must be the sum of a 
his influence in past ages? Is it too much to say " 
influence aided in the extermination of those monsters of% 












| 

*B. D. Walsh, Practical Entom 
: rE ologist, October, 1865, and November, 1866. 
gaa ta certain Entomological Speculations of the New England school 
TGJ. Bowles a of the Entomological Society of Philadelphia, Vol. II, 
„J. 8, e Occurrence ; Janadian 
WALT Ko. 4, August, ions of Pieris rape in Canada. C 
ay 
