279 
tion entered the fruit was determined from observations on individuals 
secured from band collections. These were abundant enough to give us 
the dates with a fair degree of accuracy. The number of effective day- 
degrees, 1551, or, to use round numbers, 1550, given for this event in 
the table may be considered as approximately correct and will be used 
as a basis for making corrections in the table. The dates when the first 
larve of the third generation entered the fruit were determined from a 
comparatively small number of individuals isolated for the purpose of 
life history studies, and for this reason it is quite certain that the dates 
thus obtained were somewhat later than the true dates. 
It is impossible to estimate with any degree of accuracy how much 
oi an error was made in determining dates from a too limited amount 
of material, but we can, by using data procured by studies on the rela- 
tion of temperature to the different stages and to the complete develop- 
ment period, determine the approximate minimum effective day-degrees 
which accumulate during the complete life cycle; and by using 1550 as 
the total effective day-degrees at the time when the first larve of the 
second generation appear we can determine the total effective day-degrees 
for the date on which the first egg, larve, pupze, and adults of the three 
generations may be expected to appear. 
From our studies on the relation of temperature to the development 
of the three stages we concluded (see page 280) that the minimum 
accumulation for the three stages was about 939, the average 1101, and 
the maximum about 1317; and from our studies on the life history of 
348 individuals we concluded that the minimum accumulation for the 
period of development was about 950, the average 1120, and the maxi- 
mum about 1350 (see page 259). To get the total accumulation for 
the complete life cycle, it will be necessary to add to these mimima, aver- 
ages, and maxima about 50, 75, and 250, respectively, because the deposi- 
tion of the first eggs, the time of maximum oviposition, and the laying 
*of the last eggs do not occur until about the first, the third, and the tenth 
day, respectively, after the emergence of the female. (Table 43.) 
None of the minima, 989, 1000, and 1030, obtained for the complete 
life cycle by the different methods was determined with absolute ac- 
curacy, but they were based on actual observations, and the fact that 
they do not differ very widely indicates that they are approximately cor- 
rect. For practical purposes either one might be used as the minimum, 
but the second minimum, 1000, being nearly the average of the three is 
perhaps more nearly correct than the others, and it will be used as the 
basis for the discussion which follows. 
By dividing the 1000 effective day-degrees into parts proportional to 
the minimum effective day-degrees required for the egg, larval, and 
pupal periods, making allowance for the period elapsing between the 
time of the emergence of the adult female and the deposition of the 
first eggs, and by taking 1550 (Table 42) as approximately the correct 
accumulation at the time when the larve of the second generation begin 
