224 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



behavior, "Can your science lend us aid in the warfare against our 

 enemies?" None present this afternoon will doubt for an instant 

 the commercial importance of such biological sciences as zoology, ento- 

 mology and botany, even at this time when the economic department 

 of these subjects is still in its infancy, and it is safe to say that the 

 next few years will prove the same for the science under consideration. 



It is my purpose in this paper to first point out the scope of "Ani- 

 mal Behavior" as accepted by the more progressive group of workers 

 in this field led by such investigators as Parker, Jennings et al on 

 the one hand, and Yerkes, Watson et al on the other. As just indi- 

 cated, it should be understood that there are really two more or less 

 distinct groups of workers in the science of animal behavior : the one 

 concerned mainly with the external factors — the comparative physiolo- 

 gists; and the other group concerned mainly with the internal fac- 

 tors — the comparative psychologists. 



In the second place I wish to point out some of the more recent 

 work in insect behavior, treating this phase from a more or less crit- 

 ical standpoint. 



I Scope of Animal Behavior 



The behavior of anything, whether organic or inorganic, rests upon 

 activity ; the activity of living things is determined by the interaction 

 of two classes of determining factors, viz. : 



1. Quality of the protoplasm=internal. 



2. Quality of the environment^external. 



By any change of the external agencies that act upon the organism, 

 the latter is stimulated, because irritability is a characteristic of proto- 

 plasm. Therefore a stimulns may be defined as any change of the 

 external agencies which act upon the organism, e. g., alteration of 

 temperature, moisture, amount of food, etc., — in short, the addition of 

 a new factor, or the increase or decrease in degree of an old factor. 

 Stimulation is the result of contact of a stimulus upon the living sub- 

 stance, and the fact of stimulation is made obvious by movement or 

 by a reaction of some kind. Stimuli may vary enormously in extent 

 as thermal and chemical stimuli, but the limits within which these 

 conditions act as a stimulus are very narrow, and the total range of a 

 stimulus has not equal importance. The animal lives better near 

 normal conditions than near either extreme. Every organism is 

 adapted so that it will live best at a certain degree of stimulation, 

 I. e., optimal — at the minimal or maximal death ensues. 



The reaction of an animal is carried out through the inter-relation 



