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The Bulletin 
80 per cent for six days, as contrasted with a total of 70 per cent in 
three days for the first molt. In the larvae observed there was prac¬ 
tically no difference in the numbers (thirty-one, twenty-four, twenty- 
seven, twenty-five, and twenty) molting on the seventh to eleventh days, 
inclusive. 
DURATION OF MOLTS 
(Third Molt, Fig. 21) 
The range in time from hatching to the third molt for 165 larvae 
out of 221 larvae bred from egg to purpa lias been found to be from 
8 to 31 days. The majority, however, 103 out of 165 or 62 per cent, 
molted between the eleventh and fifteenth days, inclusive (Fig. 35), 
there being practically no difference in the numbers (eighteen, twenty- 
two, twenty-two, nineteen, twenty-two) molting on the eleventh and 
succeeding days to the fifteenth, inclusive. 
2 3 4 5 6 7 8 9 10 11 12 13 
Figure 33. Curve showing the time lapsing between the first and second molts, 
one-day intervals. The mean time is shown by the dashed vertical line 
( -). 
The time elapsing between the second and third molts is comparable 
to the time elapsing between hatching and the first molt and between 
the first and second molts, the range extending from two to sixteen days 
(Fig. 36). There was, however, only one larva out of 152 larvae that 
required sixteen days between the second and third molts and none 
requiring thirteen, fourteen, or fifteen days. Hence this one larva 
may be discarded, giving us a range of from two to twelve days. These 
figures are very closely comparable to those found for the time elapsing 
between hatching and first molt and between first and second molt. In 
all, 115 out of the 152, or more than 75 per cent, molted for the third 
time between the third and sixth days after the second molt; the only 
