72 



pius ; of a lepidopterous enemy of the larger scales, like Lecanium, and 

 of an enemy of the woolly root-louse of the apple, imported from Aus- 

 tralia. 



To the above list of importations of insect parasites should be added 

 one in which I became personally interested through the kindness of 

 Dr. Riley, more important, if possible, than any of the foregoing because 

 affecting a more destructive insect of a more valuable crop. I refer to 

 a European parasite of the Hessian fly, known hitherto as Semiotellus 

 nigripes^ of Lindeman, but which should really be known as Entedom 

 epigonus of Walker, as I am informed by Prof Riley, who has com- 

 pared it with Walker's type in the British Museum. This parasite, 

 received in Hessian-fly puparia coming originally from England, was 

 successfully bred in small, inclosed plat experiments at Champaign, 

 111., and the bred adults were released in wheat fields in that State, 

 which were themselves suitably infested by the Hessian fly. Observa- 

 tions and collections made in and about those fields this season have 

 as yet failed to detect the introduced species, but this need not sur- 

 prise us, especially as the period of its emergence from the parasit- 

 ized puparia has not yet passed. Scattering widely, as these parasites, 

 probably do at best, it maybe some years, if the experiment is success- 

 ful, before their presence is made manifest. 



Exportations of American parasites, native or naturalized, have like- 

 wise been made to Honolulu, ]N"ew Zealand, and Australia, to the Cape 

 of Good Hope, aud to Alexandria in Egypt. One of special interest to 

 American entomology is a Raphidia, found to destroy the larva and 

 pupa of the codling moth in California, which seems to have been suc- 

 cessfully exported by Mr. Koebele to !Xew Zealand. 



I need not say to this Association that practical results of the highest 

 economic value have already been reported in this most interesting 

 field and that it will be a crime against the horticultural and agricul- 

 tural interests of the country to fail to provide in the most liberal way 

 for a work so sound in method and so certainly valuable in result. It 

 is eminently a national work and of far greater than national importance. 



And next we turn to a department of investigation which has been 

 commonly claimed hitherto by the economic entomologists, but which 

 really stands for the most part fairly across the boundary line of horti- 

 culture and agriculture. I refer to experiments with insecticides. So 

 far as the effect of insecticides immediately on insects themselves is con- 

 cerned, we may very properly claim this subject for economic entomol- 

 ogy; but I am not sure that we do well to abandon our proper work 

 for observations on the effect of the arsenites on the foliage of plants, 

 or for experiments with various kinds of insecticide apparatus, or for 

 any other similar subjects which do not call for the special knowledge 

 or the special methods of the entomologist, but which may very prop- 

 erly be left to the economic botanist or the expert horticultural investi- 

 gator. This subject of insecticides has been a very inviting one to the 



