384 
Intentional introductions of wild species, 
however, have almost without exception re- 
sulted disastrously. 
At various intervals between 1850 and 
1867 a few pairs of English sparrows were 
introduced into our northeastern States to 
destroy canker worms, and to-day this 
species is an ubiquitous and unmitigated 
pest throughout all the austral and transi- 
tion regions of North America, finding its 
limit only at the borders of the boreal zone, 
while the place of the injurious insect it 
was imported to destroy has been taken by 
another and worse insect pest which it will 
not touch. 
In 1872 Mr. W. Bancroft Espeut im- 
ported four pairs of the Indian mongoos 
from Calcutta into Jamaica for the purpose 
of destroying the ‘cane-piece rat.’ Ten 
years later it was estimated that the saving 
to the colony through the work of this ani- 
mal amounted to £100,000 annually. Then 
came a sudden change in the aspect of affairs. 
It was found that the mongoos destroyed all 
ground-nesting birds, and that the poultry 
as well as the insectivorous reptiles and 
batrachians of the island were being exter- 
minated by it. Injurious insects increased 
in consequence a thousand fold ; the tempo- 
rary benefits of the introduction were speed- 
ily wiped away, and the mongoos became a 
pest. Domestic animals, including young 
pigs, kids, lambs, newly-dropped calves, 
puppies and kittens were destroyed by it, 
while it also ate ripe bananas, pine apples, 
young corn, avocado pears, sweet potatoes, 
cocoas, yams, peas, sugar cane, meat and 
salt provisions and fish. Now, weare told, 
nature has made another effort to restore the 
balance. With the increase of insects due to 
the destruction by the mongooses of their 
destroyers has come an increase of ticks 
which are destroying the mongoos and all 
Jamaicans rejoice. 
The flying foxes of Australia (Pteropus 
Sp.) are animals which are very destruc- 
SCIENCE. 
[N. S. Von. VI. No. 141. 
tive to fruit in their native home. Fre- 
quently some well-meaning but misguided 
person will arrive on a steamer at San 
Francisco with one or more of those crea- 
tures as pets. While it is not probable 
that any of the flying foxes will thrive in 
northern California or in fact in Austral 
regions, the experience is too dangerous a 
one to try, and the quarantine officer of the 
California State Board of Horticulture has 
always destroyed such assisted immigrants 
without mercy. 
Less than thirty years ago (in 1868 or 
1869) Professor Trouvelot imported the 
eggs of the gypsy moth (Porthetria dispar) 
into Massachusetts. The insect escaped 
from confinement, increased in numbers, 
slowly at first, more rapidly afterwards, 
until in 1889 it attracted more than local 
attention, with the result that in 1890 the 
State began remedial work. This work has 
steadily progressed since that time and the 
State has already expended something over 
a half million of dollars in the effort to ex- 
terminate the insect, and it is estimated 
that one million five hundred and seventy- 
five thousand dollars more must be used 
before extermination can be effected. 
Contrast with this a single intentional 
importation which has had beneficial re- 
sults. The Australian ladybird ( Vedalia 
cardinalis) was introduced into California 
in 1889 with the result of saving the whole 
citrus growing industry of the State from 
approaching extinction through the ravages 
of the cottony-cushion scale (Icerya pur- 
chasi). Later importations of the same in- 
sect into South Africa and Egypt also 
resulted beneficially« 
We have thus had sufficient experience 
with intentional importations to enable us 
to conclude that while they may often be 
beneficial in a high degree they form a 
very dangerous class of experiments and 
should never be undertaken without the 
fullest understanding of the life history and 
