277 
TABLE 40—DatTes oF THE APPEARANCE OF THE First INDIVIDUALS OF THE BRooDs 
OF THE CODLING-MOTH AT OZARK, OLNEY, AND SPRINGFIELD IN 1917 
Generation Stage Ozark Olney Spring- 
i field 
Hibernating Adults May 12 May 17 May 17 
Eggs May 19 May 20 
First Larve May 27 June 1 
Mature larve © June 18 June 23 June 25 
Adults July 1 July 7 July 9 
Eggs July 11 
Second Larve July 17 
To show the relation between. the time of the appearance of the 
first individuals of each of the broods throughout the season at Olney 
Table 41 has been prepared. 4 
The same data were worked out for Ozark in 1915, Springfield in 
-1916 and 1918, and Siloam Springs, Arkansas, for 1908, and the results 
are summarized in Table 42. 
From the averages in the last column of Table 42 we find, by a little 
calculation, that the average accumulation of effective day-degrees from 
the time of the appearance of the first individuals of the first brood of 
pupe, adults, eggs, and larve to the time of appearance of the first indi- 
viduals of the second brood of the same is 979, and that the average 
accumulation between the time of appearance of the first individuals of 
the second brood of pupz, adults, eggs, and larve and the time of ap- 
pearance of the first individuals of the third brood of the same is 1082, 
the average accumulation for the complete life cycle, that is, for the 
period between the time of the appearance of the first eggs, larve, pup, 
or adults of one generation and the first eggs, larve, pupz, or adults of 
the next generation, being 1030. 
From studies on the relation of temperature to the development of 
the different stages and to the whole development period in the life his- 
tory, we know that there is practically no difference between the number 
of effective day-degrees which accumulate during these periods in the 
different generations. The differences shown by the data in the table are 
therefore undoubtedly due to the comparatively small number of obser- 
vations on which the averages were based and to the fact that some of 
the observations were made in connection with breeding experiments 
in which comparatively small numbers of individuals were used. The 
dates on which the first larve of the first generation entered the fruit 
were determined by observations on individuals reared from hibernating 
larve, and since the number of individuals thus used was very small as 
compared with the whole number in the orchard, no doubt larve began 
to enter the fruit in the orchard before the first larve were secured in 
the experiments. The dates when the first larvee of the second genera- 
