SEASONAL HISTORY. 
29 
VARIATION IN THE NUMBER OF EGOS PER CL1 9TEB. 
Under average conditions the eggs for each oviposition are all laid 
in a single cluster. In this respect exceptions occur when the female 
is disturbed in the act of oviposition or when the space is too small to 
hold all the eggs. On the other hand, it has been frequently found 
that eggs have been laid side by side by different females, so that 
from the appearance of the cluster separate depositions could not be 
told apart. In the breeding experiments clusters containing from 30 
to 35 eggs have been found quite frequently, and these figures repre- 
sent, approximately, the average number of eggs per cluster. Table 
II gives the egg deposition of 16 female beetles. As here there had 
been interference to some extent, and the beetles had been confined 
in captivity, the average number of 24 eggs per cluster was compara- 
tively low. The maximum number of eggs in one cluster was 61 and 
the minimum 4 (Table III). In the rearing cages the period for 
each separate oviposition occasionally extended over from 1 to 2 
days, rarely 3 days; normally, however, the eggs were all laid at 
once and in a single cluster. 
NUMBER OF SEPARATE OVIPOSITIONS BY INDIVIDUAL FEMALES. 
Different female beetles have displa}^ed considerable diversity in the 
number of times of oviposition. In the experimental work 8 individ- 
uals failed to deposit any eggs ; others, as recorded in Table II, ovipos- 
ited from 1 to 9 times, or, on an average, 4 or 5 times. Similarly, the 
length of time between each oviposition is variable. An average of 4 
days elapsed between each oviposition. Often the interval has been 
only 1' da} T , while in the other extreme in one case the interval was 15 
days. (See Table IV.) 
Table IV. — Number of days between ovipositions of (he grape root-norm as observed 
during 1909 in breeding cages at North East, Pa. (Supplementary to Table II.) 
No. of ex- 
periment. 
Periods between ovipositions. 
Total. 
A \ -er- 
ase per 
female. 
I. 
II. 
in. 
IV. 
V. 
VI. 
VII. 
vm. 
1 
3 
5 
1 
2 
6 
5 
14 
2.0 
5.0 
4.7 
2 
3 
11 
2 
4 
5 
13 
7 
6 
3 
5 
2 
24 
19 
8.0 
3.8 
6 
4 
3 
7 
8 
3 
4 
4 
2 
3 
2 
3 
3 
2 
1 
5 
22 
4 
15 
13 
2.7 
4.0 
3.7 
2.6 
9 
10 
1 
5 
7 
2 
3 
3 
11 
1 
12 
13 
4 
2 
1 
3 
2 
1 
5 
15 
2 
4 
5 
4 
2 
T 
5 
4 
3 
3 
2 
5 
4 
26 
14 
16 
22 
3.2 
2.0 
4.0 
7.3 
14 
15 
16 
Total.... 
Average.. 
52 
4.0 
53 
4.8 
37 
3.4 
21 
3.0 
14 
2.8 
7 
2.3 
7 
2.3 
9 
4.5 
200 
53.0 
4.07 
