February, '09 J JOURNAL OF ECONOMIC ENTOMOLOGY 29 



tomological response — of ecological interaction — we economic ento- 

 mologists have been busy all our working lives, whether we have made 

 precise note of the fact or not. We are indeed, whether we have 

 meant to be or not, the leading ecologists in America today. As prac- 

 tical entomologists, however, our work has run, as a rule, along too 

 narrow lines to give us an adequate view and command of the whole 

 field; and there is now coming to our aid a group of active young 

 geologists who, unfettered by any responsibility for an economic re- 

 sult, are working out the relations of organisms to peculiarities of lo- 

 €al situation and condition, who are searching for the causes of local 

 ■distribution and abundance in the facts of interaction and adapta- 

 tion, and who are tracing also the history and development of this 

 ■distribution and association of species by processes as careful and as 

 promising of fruitful result as those which have given us the geological 

 Mstory of the globe. All of their most general, most important re- 

 sults must apply in our special field; and a knowledge and appreci- 

 ation of their method wdll lead us to study our larger problems in the 

 large way; to treat an entomological inquiry as merely a special item 

 in a broad investigation, which shall include, from the beginning, all 

 the factors which can enter into it or influence it to any significant de- 

 gree. It is particularly important to us that we should have clear 

 ideas of the system of relations existing in our several districts be- 

 tween insects and the organic world at large, before civilized man 

 appeared upon the scene, with his associate group of intrusive animals 

 and plants ; for we can only modify or disturb, often to our own dis- 

 advantage, this primitive natural order, and can never wholly replace 

 it. The same forces which established it in the beginning are con- 

 stantly at work, not perhaps to reestablish the old order, but at least 

 to rectify disturbances due to us and to establish finally a new order 

 of equilibrium between the remaining remnants of the old and the 

 intrusive elements we have introduced. 



Permit me to give you a simple illustration of the application of 

 the ecological method to the organization and discussion of the data 

 of an economic problem ; and for this purpose I will take the corn- 

 insect problem as the one with which I am, perhaps, most familiar. 

 From the ecological point of view a corn field is a situation — a hab- 

 itat, a biotope — and its inhabitants are a biological association, or a 

 biocoenose. The assemblage of plants and animals characteristic of 

 it is found together in the corn field because of its special fitness for 

 their occurrence and their maintenance there, and this assemblage has 

 had its history of first appearance and gradual transformation. It has 

 its important relations to surrounding situations, and to their charac- 



