546 



SCIENCE. 



[N. S. Vol. IV. No. 94. 



commend the course taken by some of our 

 economic entomologists who, in connec- 

 tion with their other work, make a system- 

 atic study of some family or group of 

 insects, or study thoroughly the anatomy 

 or embryology of one or more species. 

 Even a fragment of such study will some- 

 time prove useful, since it forms a link in 

 the great chain of human knowledge and 

 each link forged into it tends to strengthen 

 and make it more useful. I have no sym- 

 pathy with those who work only in one re- 

 stricted field till they become so narrow 

 that they can appreciate nothing except 

 what is to be found in their own extremely 

 narrow groove. The entomologist who 

 broadens the horizon of his observations 

 becomes better able to grasp and compre- 

 hend the great problems presented to him. 

 With the discovery of insecticides came 

 the necessity for various kinds of apparatus 

 for the application of them, and here again 

 there has been an evolution which is still 

 going on. Many of the spraying pumps, 

 nozzles and other apparatus first placed on 

 sale are no longer in use, but greatly im- 

 proved kinds are on the market, and inves- 

 tigations are still giving us improvement 

 after improvement, some of which, unfor- 

 tunately, are no improvement at all. On 

 the whole, however, the insecticide appara- 

 tus of to-day is greatly superior to that of 

 a decade ago. 



THE FUTURE OF ECONOMIC ENTOMOLOGY. 



It seems to me that in the future devel- 

 opment of economic entomology we have 

 need of the chemist and of the physiolo- 

 gist. Some work has already been done 

 on the use of Paris green and lime, but the 

 results do not appear to be beyond question. 

 It is to be hoped that the investigations 

 already made in the work on the gypsy 

 moth, as well as those not yet completed, 

 may prove of value in operating on other 

 species of insects. This work has already 



given us arsenate of lead and arsenate of ba- 

 rium as insecticides, and investigations are 

 still going on concerning the nature of the 

 intestinal secretions of this insect and the 

 poisons that will most readily react on 

 these secretions and thereby destroy it. 

 It may be that investigations by the 

 chemist and physiologist, working together 

 along these lines, may give us something 

 in the future superior to anything in 

 use at the present time. The three most 

 important characteristics of an insecticide, 

 which must be kept constantly in mind, 

 when investigating a new or untried poison, 

 are : 1st. It must kill the insects quickly, 

 the more quickly the better. 2d. It must 

 not injure the foliage when used in as large 

 proportion as one may need for the destruc- 

 tion of the insects. 3d. It must be cheap 

 enough to come into general use. There 

 are other considerations of more or less 

 importance, as the ease with which the in- 

 secticide may be applied, its liability to 

 clog the nozzles or corrode and injure the 

 apparatus, and, in fact, any objection that 

 will prevent the substance from coming into 

 general use. 



After one has made valuable investiga- 

 tions and discoveries in economic entomol- 

 ogy, it remains for him to publish his dis- 

 coveries in such a place as will be accessible 

 to those who most need this information, 

 and in such a manner as to lead them to 

 read the paper carefully and intelligently. 

 I know very well that there are thousands 

 of persons who receive our bulletins who do 

 not even look them over. I was told by 

 the editor of one of our leading agricultural 

 papers, a few years ago, that he sent out a 

 circular letter to his subscribers, asking 

 what changes, if any, they would like to 

 have him make in his paper, and a large 

 percentage of them requested him to give 

 them more stories ; and I have sometimes 

 wondered if the information given in our 

 bulletins were presented in the form of a 



