The Bulletin 
61 
striking point being the larger number, 83 or more than 54 per cent 
of the total number, molted between the fourth and fifth days after 
the second molt. 
DURATION OF MOLTS 
(Fourth Molt, Fig. 22) 
The time elapsing between third and fourth molts ranges from 2 
to 15 days (Fig. 37). Ninety out of the 130 larvae, or about 70 per 
cent, molted between the fifth and eighth days, inclusive. Six days in 
this case is more pronounced than in any of the other curves for lapsed 
time (see Figs. 32, 33, and 36). 
The total time from hatching to the fourth molt ranges from 12 to 
40 days, and there is a great tendency to variation (Fig. 38). The 
principal mode seems to occur around the nineteenth day. 
DURATION OF MOLTS 
{Fifth Molt, Fig. SO) 
(From fourth larval molt to pupation.) 
The time between the fourth larval molt and pupation (fifth molt) 
is decidedly longer than that recorded for previous molts, ranging from 
three to thirty-one days. For the 149 larvae for which we have been 
able to obtain the fiftli-molt interval, there seems to be a tendency 
for the results to group themselves around two modes, one at 8 days 
and the other at 13 days. The mean, however, is 12.4 days, suggesting 
that the latter is perhaps the true mode, and that the apparent mode at 
8 days is due to insufficient numbers (Fig. 39). 
The total time for larval development, i. e , from hatching to pupa¬ 
tion, ranges from 22 to 54 days (Figs. 40 and 41). The majority, 
