February, ’24] 
BABCOCK: CORN BORER BIOLOGY 
121 
accurate means for appreciating the potentiality of the insect in various types of 
climate. 
The basis for the investigation of the climatic relationships to the 
seasonal history of the corn borer might be said to be the necessity of 
obtaining information, in advance of dispersion to new localities, con¬ 
cerning the potentiality of the insect in its new environments. It is 
not possible in the time alloted for presentation of this paper, to give 
other than a very abstracted account of the projects which have been 
under way in connection with the problem. The research has followed 
three main lines, first; the determination of the possibility of two dis¬ 
tinct species occupying the one and two generation areas; second; 
the possibility of a geographical race, or strain, and third; the intimate 
study of the environment both experimentally and hypothetically. 
It was at first planned to formulate-temperature correlations upon the 
data obtained from controlled temperature experiments, but it was found 
impractical and inaccurate to base predictions of seasonal history on the 
fluctuations of one factor. The conception of the development curve in 
relation to temperature as a true hyperbole does not hold except within 
certain limits. The other important climatic factors exert a distinct 
influence upon the physiological limits of the insect and upon the rate 
of development or velocity. It was found to be impracticable to com¬ 
pare localities by means of the corrected form of evaluated temperatures, 
since in a type of environment distinct from the one in which the 
material lived with which the controlled experiments were conducted, 
there would result a different reaction to the fluctuations of the climate. 
Until more detailed knowledge is gained concerning the physiology of 
the insect, the investigation will be chiefly field experiments and observa¬ 
tions, 
The experiments conducted with quantities of one and two generation 
material have shown that the progeny produce fertile eggs and in normal 
numbers, and the seasonal history in the majority of cases consists of 
two generations. Individuals which have been transferred from one to 
two generation areas, and vice versa, and reared in field cages, have 
persisted in practically the same seasonal history, after three years’ 
study, as they were accustomed to in their previous environment. 
Through the suggestions of Dr. Victor E. Shelford, of the University 
of Illinois, there was evolved from the constant temperature experiment 
data, an expression for the relation of temperature to development 
which has proved quite satisfactory for comparisons of seasonal history 
within a restricted area. However, it is believed that this type of tern- 
