ON THE IMPORTATION OF BENEFICIAL INSECTS 

 FROM ONE COUNTRY TO ANOTHER. 



BY L. O. HOWARD, Ph.D. 



Delivered before the Society with stereopticon illustrations, 

 January 13, 1906. 



(Author's abstract.) 



There are many large groups of insects which are parasitic 

 in their habits and which destroy other insects. There are other 

 large groups which are predatory in their habits and feed upon 

 other insects. There is hardly an injurious insect which does 

 not have its natural enemies in its own class. Sometimes the 

 natural enemies will have the upper hand and the injurious species 

 will be greatly reduced in numbers. Again the natural enemies 

 will be reduced and the injurious species will abound. AVherever 

 an injurious insect exists under normal conditions and in its orig- 

 inal home, its natural enemies as a rule keep it in check and pre- 

 vent its unlimited multiplication. But now with the large-scale 

 •expansion of agriculture and horticulture, and with the constantly 

 increasing rapidity of traffic between countries, it has frequently 

 happened that injurious insects have been introduced from one 

 country to another without their natural enemies, and have conse- 

 quently multiplied to an enormous degree. The United States 

 has suffered especially from accidentally introduced insect pests 

 mainly coming from Europe. About one-half of the injurious 

 insects of first-class importance now existing in the United States 

 were accidentally introduced from some foreign country. 



A great interest in the handling of insects by means of their 

 natural enemies has constantly been increasing in many parts of 

 the Avorld since the year 1888 when the strildngly successful search 

 for the natural enemies of the fluted scale (Icerya purchasi) was 

 begun under the auspices of the United States Department of 

 Agriculture. But the idea was an old one. Dr. Asa Fitch, for- 



