Economic Importance of the Parasites of Coccidie. 229 



report on the San Jos^ scale in Japan, after stating that 

 this Coccid has been lately established in that country, 

 says, " the scale is attacked also by one or two Chalcid 

 parasites, presumably the ones we have in America, and 

 brought to Japan with the scales or cosmopolites." 

 It is very probable that the pernicious scale is really a 

 native of Japan,* and that this is the reason why it is not 

 injurious there ; scale insects are very rarely destructive 

 in their natural homes because of the natural relations 

 that exist between them and their destroyers. Sasaki f 

 says the principal enemies of Aspidiotus pcrniciosus 

 are a red mite, Coccinella japonica, and a Chalcid fly 

 (? Coccophagus). He states that " in the specimens of the 

 scale allied to the pernicious scales collected by myself, I 

 have often found a roundish, or rather small irregular open- 

 ing in most of the scales, which is evidently perforated by 

 the parasitic Chalcid fly " (p. 172). 



My object in writing this paper is not merely to add a 

 few items to the facts of Economic Zoology, but rather to 

 point out how very much remains to be discovered, even as 

 to matters that have a very serious economic bearing. This 

 is a somewhat invidious task, for it seems to involve a 

 reflection on those who have worked at the subject. I 

 should like to say that I hope no inference of that kind 

 will be drawn from anything I have said. The work done 

 by many Economic Entomologists is admirable, and the 

 American school has accomplished wonders ; and in nothing 

 are they more worthy of admiration than in their readiness 

 to modify their methods in accordance with the advance of 

 knowledge. 



It is encouraging to find how clearly it is being recognized 

 that the chief consideration of the Economic Entomologist 

 should not be the mere prescription of modes of destruction, 

 but should be rather in the direction of learning the facts 

 of the natural history of the pests. It may be predicted 

 that the Economic Zoology of the future will be generally 

 recognized as being "Applied Natural History." The 

 prevention of the undue increase of enemies should there- 

 fore be the object of the economic investigator, so that 

 wholesale destruction of life should be rarely, if ever, 

 required. 



* See Marlatt and others in Bull. U.S. Dep. Agric. Ent, xxxi, 

 1902, pp. 41-48. 



t Annot. Zool. Japan, iii, p. 171. 



