October, '09] JOURNAL OF economic entomology 323 



Hessian fl}-, gypsy moth, brown-tail moth, cotton boll weevil and cod- 

 ling or apple worm. When first introduced these pests, being un- 

 molested and not kept subdued bj^ their natural enemies, which were 

 left behind, often multiply prodigiously and make for themselves 

 unheard of records for destructiveness. In such eases nature's bal- 

 ance is not restored until their old enemies are imported to prey upon 

 them, or until parasitic and predaceous forms, native to their new 

 home, acquire a taste for them. A striking illustration of the benefits 

 which may sometimes be obtained by fighting insects with insects was 

 given by the importation of the Australian lady-bird into California. 

 The cottony cushion scale, a citrus pest. Avas introduced into Cali- 

 fornia from Australia about 1868. B}^ 1886 it had spread to eight 

 different countries, and three years later so much of the orange terri- 

 tory had become infested and so helpless were our entomologists and 

 the citrus producers before its rapid march that the entire citrus in- 

 dustry in the state seemed doomed, and many of the growers had al- 

 ready" abandoned or were preparing to abandon their business when 

 the advent of the lady-bird happily restored confidence and the fluted 

 scale has not been a very important factor in California orange culture 

 since. Something like 127 lady-beetles were received from Australia 

 and, from the progeny of these bugs alone. California was completely 

 stocked and practically cleared of the scale in about eighteen months. 

 A few years since, while entomologist of the Florida Experiment Sta- 

 tion, the writer had the pleasure of repeating this California ex- 

 ploit in the Florida orange groves, where the same scale had become 

 accidentally established. Another parasite brought over from Aus- 

 tralia at the same time as the lady-bird has cleared many of the olive 

 groves of California of the black scale and has been a great factor 

 in preventing headway by this pest. At present the United States 

 Bureau of Entomology, in conjunction with the Massachusetts au- 

 thorities, is making importations of parasites and predaceous insects 

 for trial against the gypsy and brown-tail moths on the largest scale 

 that has ever been undertaken. Hundreds of thousands of host in- 

 sects, containing parasites, have been brought each year from a large 

 part of their geographic range. ]\lore than forty species of parasites 

 have thus been brought over, bred and liberated. Several of them 

 have certainly established themselves in New England and there 

 seems to be every reason to believe that speedy success will be reached. 

 As a summary of the general teaching of the paper, I cannot do better 

 than close with the following quotation from the acute writings of our 

 government's entomological chief. Dr. L. 0. Howard: 



"Man is but one of the forms of life struggling for existence, at con- 



