134 rN^TEODUCTIOIT OF INSECTS. 



which would prove ahnost fatal to the entire harvest, were it not 

 that, in the great territorial extent of the United States, there is 

 room for such differences of soil and climate as, in a given year, 

 to present in one State all the conditions favorable to the iacrease 

 of a particular insect, while in another, the natural influences are 

 hostile to it. The only apparent remedy for this evil is, to bal- 

 ance the disproportionate development of noxious foreign species 

 by bringing from their native country the tribes which prey 

 upon them. This, it seems, has been attempted. The United 

 States Census Eeport for 1860, p. 82, states that the 'New York 

 Agricultural Society "has introduced into this country from 

 abroad certain parasites which Providence has created to counter- 

 act the destructive powers of some of these depredators." * 



This is, however, not the only purpose for which man has 

 designedly introduced foreign forms of insect Hfe. The eggs of 

 the silkworm are known to have been brought from the farther 

 East to Europe in the sixth centm-y, and new silk-spinners which 

 feed on the castor-oil bean and the ailanthus, have recently been 

 reared in France and ia South America with promising success.f 

 The cochineal, long regularly bred in aboriginal America, has 

 been transplanted to Spain, and both the kermes insect and the 

 cantharides have been transferred to other climates than their 

 own. The honey-bee must be ranked next to the silkworm ia 

 economical importance. This useful creature was carried to the 

 United States by European colonists, in the latter part of the 

 seventeenth century ; it did not cross the Mississippi till the close 

 of the eighteenth, and it is only in 1853 that it was transported 

 to California, where it was previously unknown. The Italian 

 bee, which seldom stings, has lately been iatroduced into the 

 United States.:): 



* On parasitic and entomophagous insects, see a paper by Rondani referred 

 to p. 117 ante. 



f The silkworm which feeds on the ailanthus has naturalized itself in the 

 United States, but the promises of its utility have not been realized. 



X Bee-husbandry, now very general in Switzerland and other Alpine regions, 

 was formerly an important branch of industry in Italy. It has lately been 

 revived and is now extensively prosecuted in that country. In fact, the mar- 

 ket demand for Swiss honey has become so great that the producing powers 

 of the bee are not found equal to meet it, and I am informed by an in 



