i82 THE ANIMALS AND MAN 



their beneficent work, increased in numbers and were later 

 distributed in scale-infested orange orchards. In a few 

 years they had practically relieved the California orange 

 growers of all anxiety concerning cottony cushion scales. 

 And now they are the standard and easily and cheaply 

 applied remedy for scale insects of this kind. 



This is so far the most successful case of the introduction 

 and establishing in America of one insect species to attack 

 and keep in check another insect species. But numerous, 

 other introductions ha\'e been made both of predaceous 

 insects (lady-bird beetles, etc.), and parasitic insects (kinds 

 that lay their eggs in or on other kinds so that the hatching 

 young feed on the living bodies of the hosts). Among the 

 most conspicuous examples of this modern way of fighting 

 insect pests is the work now being done, chiefly under 

 go\'ernmental control, in connection with the gypsy moth 

 plague in New England. 



In 1869 an astronomer and amateur naturalist living in 

 Medford, Mass., was experimenting in cross breeding various 

 silk-producing moths trying to produce a hardier silk maker 

 than the Chinese mulberry silkworm. He caused to be 

 sent to him from Europe the eggs and larvce of various 

 cocooning moths and among them those of the gypsy. 

 In some way eggs or young of this moth, which has long been 

 known as a pest of shade and forest trees in Europe, escaped 

 from the experimenter's rooms and found congenial growing 

 and breeding places in the neighborhood. The naturalist 

 gave public notice of the escape but not until ten or twelve 

 years after was the new settler noticed as abundant enough 

 to be a nuisance and a menace, and not until 1889 was its 

 spread sufficiently wide to attract general attention. In 

 1890 a town meeting appropriated $300 to exterminate the 

 pest. These $300 did not do much exterminating and from 

 that time until today it has been a constant struggle between 

 moth and the people of New England backed by the United 



