402 
Journal of Agricultural Research 
Vol. XXIV. No. 5 
Both Felt (4, p, 6J) and Slingerland (12, p. 210) report the results of 
trap lantern collections at Ithaca, N. Y., and, although the number of 
moths taken is too small to more than indicate the facts, they seem to 
show that the two periods of greatest abundance lie between June 10 
and 20 and July 8 and 20. More than one month is required for the 
development of a generation, so these Ithaca figures must be taken 
subject to revision. 
REARING RECORDS 
Laboratory records fully bear out the foregoing observations. Table 
I is a compilation of all the rearing records available for individuals 
under observation from egg to adult. It will be noticed that during the 
summer the interval between oviposition and the emergence of the adult 
is from 42 to 70 days, averaging about 55 days. Allowing three days for 
the preoviposition period brings it to 58 days, slightly less than two 
months from egg to egg. This works out almost exactly in the table; 
one generation from May 23 to July 21;‘the second from July 21 to 
September 11; and the third, or overwintering generation, from Septem¬ 
ber 11 to the following May. It will be noted also that many of the later 
larvae of the second generation, those coming from eggs laid after August 
I, emerged the following spring. Thus it is safe to conclude that in 
Teimessee there are normally three generations per year, some of the 
second and all of the third overwintering as larvae. Farther north the 
third doubtless becomes smaller and may completely disappear, leaving 
larvae of only the second generation to pass the winter. 
Tabi.^ I .—Rearing records of Crambus mutabilis under observation in the laboratory 
or insectary from egg to adult ' 
A.... 
A. ... 
ms-- 
1775-• 
B. ... 
c.... 
c.... 
E.... 
1777.. 
15268, 
15284 
H.... 
H.... 
G.,.. 
1792. 
J 
J 
J 
J 
Cage No. 
Eggs laid. 
Moth out. 
Number 
of days. 
Sex. 
Number 
of moths. 
May 23 
23 
23 
23 
26 
26 
26 
27 
30 
June 3 
6 
9 
9 
12 
12 
16 
July 21 
21 
21 
21 
July 8 
Aug. 5 
July 30 
Aug. 2 
July 7 
8 
Aug. 5 
July II 
31 
26 
26 
31 
Aug. 12 
July 31 
Aug. 2 
12 
Sept. 3 
4 
5 
7 
21 
8 
21 
9 
46 
74 
68 
71 
42 
43 
71 
45 
62 
53 
50 
52 
64 
49 
51 
57 
44 
45 
46 
48 
49 
50 
c? 
cT 
9 
<? 
9 
c? 
c? 
<? 
c? 
c? 
9 
9 
6 S- 
6 9 
I <? 
I 9 
1 S 
2 9 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
1 
2 
8 
5 
12 
2 
3 
21 
14 
55 
I 
1 The records designated by letters were made in 1914; in other cases the first two figures of the cage num< 
ber indicate the year in which the records were made. 
