34 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



to be making invidious distinctions. Yet to everyone, certain subjects 

 appeal more strongly than others, and on this basis of personal in- 

 terest alone, a few which have for one reason or another appealed 

 strongly to the speaker, may be referred to briefly. 



The researches of Bachmetjew upon the temperature relations in 

 insects, followed by those of others who have applied his discoveries 

 to the preservation of life during the winter — investigations in which 

 Sanderson and others have been active in this country — are full of 

 significance. Closely connected to this have been the studies of the 

 relation of temperature to development, one paper on which was pre- 

 sented at the last meeting of this Association. It is my behef that 

 work along these lines has only just been begun, and that the results 

 will prove of great importance, not only to pure science but to economic 

 entomology. 



Another field which promises to contain much of great value is that 

 of the relation of food to reproductive activity and to longevity. 

 Though thus far investigated mainly with reference to parasites, it 

 would seem to be of importance everywhere, and the subject de- 

 serves far more extended exploration. 



The subject insecticides has already been referred to, but how little 

 we really know as to the way in which some of them actually kill in- 

 sects has been most interestingly shown by Shafer. More work in this 

 field is waiting, and results of an importance which cannot yet be es- 

 timated are sure to come. 



Whether it is possible by methods of plant breeding to produce 

 varieties having greater freedom from the attacks of insects than those 

 now in use, is a field which so far as I know has not yet even been seri- 

 ously considered. The only cases which occur to me are the recom- 

 mendation to select varieties of wheat which ^Hiller" freely, as a means 

 of saving wheat fields liable to attack by the Hessian Fly, and the 

 unfortunate one where two New Jersey nurseries apparently spread 

 the San Jose Scale over the country in their attempts to find a Cur- 

 culio-proof plum, and even those do not come strictly under the head 

 of actual plant breeding. Whether this field will prove productive 

 no one can tell at present, and actual exploration will be necessary to 

 determine whether it is to be of any value. 



The sensation produced by the appearance of a bulletin a few years 

 ago upon the arsenical poisoning of fruit trees by spraying is still well 

 remembered by us all. Here was a new field for exploration and a 

 number of workers have now attacked this subject. Whatever the 

 final conclusions reached may be, more information along this line is 

 necessary, and it may be permissible to suggest that a knowledge of 

 what ''thou shalt not" do in entomology is ofttimes as valuable as 

 knowledge in its positive form. 



