REPORT OF THE ENTOMOLOGIST. 



325 



which species are beneficial, and which injurious; and the ability to 

 distinguish between friend and foe is of the first importance in coping 

 with the latter, for it is a notorious fact that the farmer often does more 

 harm than good by destroying the former in his blind efforts to save his 

 crops. 



"A great deal has been written and published of late years on the 

 subject of economic entomology, much of it, however, at second hand ; 

 for, unfortunately, the original workers are few. That comparatively 

 small progress has hitherto been made, is due to this last fact, as well 

 as to the intricacies and complex nature of the subject. The economic 

 entomologist, to do effectual work, must possess, not merely a knowl- 

 edge of the particular injurious species, and its habits, with which he 

 wishes to deal, but must study its relations to wild plants as well as to 

 the particular cultivated crops it affects. He must also study it in its 

 relations to other animals. Indeed, its whole environment must be 

 considered, especially in connection with the farmer's wants, the natu- 

 ral checks which surround it, and the methods of culture that most 

 affect it. The habits of birds, the nature and development of minute 

 parasitic organisms, such as fungi, the bearing of meteorology, must all 

 be considered, and yet, with the knowledge that a study of all these 

 bearings implies, he will frequently fail of practical results without ex- 

 periment and mechanical ingenuity." 



The earlier writers on applied entomology, as Peck, Harris, Fitch, 

 Walsh, Le Baron, Glover, did good work in unraveling the life myste- 

 ries of injurious species, and framed their advice to the cultivator from 

 these entomographic studies. Mere study of this kind alone, however, 

 while essential, is not often productive of those important practical re- 

 sults which follow' when it is combined with field work and experiment 

 by competent persons and upon scientific principles. Many of the rem- 

 edies proposed and recommended in the agricultural press are either 

 ridiculous or else based on misleading empiricism, and economic ento- 

 mology, as a science, is of comparatively recent date. 



The time limit of this paper will permit but the briefest reference, by 

 way of illustration, to some of the means alluded to. I have already 

 indicated the prime importance of a knowledge of the life-history of the 

 species to be dealt with — a knowledge that can come only by direct and 

 careful inductive research carried on sometimes during many years; for 

 every insect exists, in the course of its development, in four different 

 states, three of them more or less abruptly marked by metamorphosis 

 and each with habit and environment peculiar to it. Thus the same 

 species may inhabit earth, air, and water at one or the other period of 

 lite, and yet be quite incapable of a change of environment at any one 

 peri (1. It took me live years, with a number of observers at command, 

 to definitely settle some points in the life history of the Cotton worm 

 [Al ti<t xyVnm, Say), and with all the resources of the French Govern- 

 ment — its liberal premium, its superior and sub-commissions appointed 

 for the purpose and at work for the past fifteen years — there is much 

 that is yet mooted in reference to the Grape Phylloxera. You have all 

 heai (I of this insect, and perhaps a brief statement of its habits will 

 serve to illustrate the complicated problems with which the economic 

 entomologist often has to deal. 1 quote in substance from one of my 

 reports : 



"The full life history of the species exhibits to us no less than five 

 different kinds of eggs. 1. The regularly ovoid egg, 0.25 mm long and 

 half that in diameter, of the normal, agamic, and apterous female, as it 

 is found upon the roots. 2. The similar but somewhat smaller egg of 



